Chapter 2: Building Games

The length of a campaign can range from just a few sessions to many years. Two main factors determine campaign length: how much time you need to complete the story and how much time players want to devote to the game.

You can estimate how long a campaign will take by looking at the amount of time you actually have to play, or the number of character levels you intend the characters to advance. It typically takes three to four sessions for a group to level up. Since you'll probably cancel sessions on occasion, playing once a week for a year results in roughly a 14-level campaign, playing every 2 weeks for a year gives you an 8-level campaign, and playing monthly allows for a 5-level campaign. If you play monthly, you might consider holding longer sessions and using fast advancement (800 XP to level up) or choosing story milestones to reach the next level. Some groups using milestone leveling might level up every session, or spend several sessions experiencing the new abilities available to them at a certain level, at group discretion.

Some campaigns go all the way to 20th level, ending after the player characters attain the height of power and confront the greatest threats any mortal could face. Others end at a lower level, after the group takes down a major villain or solves a crucial problem. And still other campaigns end when players become unable to attend or decide it's a good time to stop playing.

You should have an end point in mind when you start a campaign. Still, you have to be flexible since you're telling the story alongside other players, and your initial expectations for the campaign might change over time. It pays to be conservative when estimating your campaign's length and scope. It's always tempting to run a 20-level epic campaign with complex, interwoven plots, but such games can fall apart long before the end if your group can play only once a month and the players have other responsibilities.

It's also important to talk to the other players about your progress and everyone's engagement with the campaign and characters. When you think you're heading toward a satisfying conclusion, check in with the other players. You might say, “I think we have about two sessions left. Does that work for everyone? Is there any unfinished business you want to take care of?” or “I know we said today was our last game, but the party's last wish ritual to reincarnate on another planet together inspired so much roleplay that I'm excited about playing a one-shot with those characters. Is anyone interested? Or do you want to start a new game with new characters?” This lets you gauge whether your assumptions match up with the rest of the group—and allows you to make any necessary adjustments if they don't.

When building your campaign, you can use these structures as a starting point. The Adventure Design section explains various styles of adventures on that can be used to inspire the creation of the adventures in your campaign. For a campaign consisting of multiple adventures, you'll need to add some story elements that speak directly to the characters in your game rather than just to the events of the adventure. In other words, the characters should have individual goals in addition to the group's overall goals.

The themes you choose for your campaign are what distinguish it from other campaigns. They include the major dramatic questions of your story and the repeated use of certain environments or creatures, and they can also include embracing genres such as dystopian, high-tech, fantasy, wartorn, into the unknown, horror, weird, and more (see Galaxy Guide). The themes you choose for your campaign also suggest storyline elements you might use.

A storyline's themes usually relate to the backstories, motivations, and flaws of the player characters and villains. For example, if you've chosen revenge as one of the themes of your game, you might introduce a villain whose quest for revenge tears their life apart and causes tragic harm to those around them. You might choose a theme of love, leading to nonplayer characters involved in doomed romances, seeking to regain lovers they've lost, or courting the player characters.

You might choose to mix elements of classic high fantasy, such as the content of the Pathfinder Roleplaying Game, into your campaign. See Chapter 5: Anachronistic Adventures for advice on how to combine this material with a Starfinder campaign, or vice versa.

In a campaign that includes multiple adventures, a smooth transition from one adventure to the next ties the story together. You might use NPCs who could appear in both adventures, a treasure or clue found in one adventure that becomes important in a later one, or even fallout from choices the PCs made in one adventure that causes the next adventure to take place or creates unforeseen complications. Related locations can help, too. Adventures that take place in the same or neighboring regions of space have an inherent link. If they take place in two different places, you'll need a reason the PCs should travel between the two, and you can use this journey as a short, interstitial adventure or a risky trip through the Drift (or deep space) where random encounters with dangerous and marvelous alien creatures might occur.

Using similar locations and related creatures helps you form connections between disparate adventures. For example, you might have the players explore a frozen corporate outpost on Vesk-7 early on, then later travel to an icy plane filled with more difficult challenges that can be overcome using knowledge they've previously developed. Likewise, glitch gremlins might be tough enemies for your group at low levels, but as the PCs attain higher levels and the gremlins become mere minions of a powerful fey technomancer, the players feel a sense of progression. Over time, the players feel like their characters are becoming experts at negotiating with Veskarium soldiers, navigating the stars, battling daemons, navigating the Drift, or dealing with whatever the recurring elements are.

Consider how each adventure's theme plays into the campaign as a whole. You might want to keep similar or recurring themes, especially if each adventure is part of one overarching storyline. On the other hand, this can feel repetitive, and some groups prefer variety and seeing their characters play off of different situations. To convey shifting themes, you can show established parts of the world changing to reflect the new theme. For instance, if you're switching from a dystopian campaign to one with futuristic and fantasy elements, the PCs could buy their impounded starship back from an azrinaran oligarch on Apostae but then face magically controlled fungal constructs and corrupted Skyfire pairs on Triaxus after they arrive looking to join the legendary Skyfire Legion.

Ask what everyone enjoys and what your players would like to see in the game. You can use these ideas as touchstones to build off of. When you get into the campaign itself, the PCs' goals come to the forefront. Find out what each character wants to achieve and look for opportunities you can place in the game world and its adventures. Consider which part of the game most closely ties to each goal. A PC who wants to become a celebrity needs fame and interpersonal connections, so you can use NPC interactions to give them the resources they need. For a character whose purpose is to help people in danger, build some encounters that include people who need to be rescued. A character who wants to upgrade their gear and become more powerful will most likely enjoy getting a chance to find or shop for new equipment. Character goals can always be progressed through roleplay in downtime or between sessions.

Look for good times to recap the state of a character's goals and remind the player how their character has progressed, particularly when something changes in relation to their goals. Consider rewarding players who keep track of their character'sgoals and their progress, potentially giving out extra Hero Points to incentivize engaging with the campaign's long-term story. The Long-Term Goals section gives you more details on how you can use goals in downtime.

As the group moves through the campaign, the events of their adventures and downtime should change the world and galaxy around them. Show this through the responses the characters get from other people, the scenery they see around them, and their environment. You might be able to anticipate some changes, but most will come up in play and require you to make adjustments later on.

Enemies come and go, but a nemesis is forever. Consider including villains who can appear multiple times over the course of several adventures. They don't necessarily need to be masterminds. Imagine an unscrupulous mercenary who works for major villain after major villain, or a series of clones deployed over and over by a corrupt corporation or galactic leader. When you create a recurring villain, it's best not to make them too integral to the story since the PCs might take them down earlier than you expect! Have some contingency plans in place.

The advice about roleplaying NPCs applies especially to these recurring villains. As they reappear throughout the campaign, they should change in some of the same ways PCs do. Think about how previous run-ins with the PCs have shaped the recurring villain's emotions and plans. Which PC do they have the biggest grudge against, and why? Do they bear scars from previous battles? Have they developed a countermeasure against a PC's spells or tactics? What's memorable about them?

Before your first session begins, communicate back and forth with the players about the following details to make sure you've planned your campaign to fit their preferences, then recap and communicate your final decisions.

• Establish the expected schedule and, generally, how long you expect the campaign to last. It's okay if you aren't certain about the total length, but you should still give an estimate.
• Inform the players when and where the first session will take place, what they should prepare in advance, and what materials to bring. If you're running a session zero to create characters first, let them know. You might also need to tell them whether to bring food, drinks, and other supplies beyond what they'll use for the game itself if you're playing in person.
• Let the players of know any restrictions or extra options for character building. Even if you plan to run a session zero, give them a heads-up before the session starts.
• Tell the players where in the game universe the first session will take place.
• Give the players a basic idea of the genre or theme.

A campaign might have a well-planned, emotionally resonant ending that executes perfectly, or the group might die in a ridiculous fashion at the worst time possible. The ending doesn't always match the idea you had in your head at the start of the campaign. Check in with your group, especially when you're getting close to the end of each adventure, to see how long they want the campaign to go on and if they're still having fun. Check in with yourself, too, and express your opinion to the other players. Ideally, you know at least a session in advance that the end is coming, allowing you to prepare for a thrilling conclusion. You might plan for the final session's gameplay to be a bit shorter—possibly just one big showdown—to allow time for an epilogue and for the group to reminisce and decompress at the end.

An epilogue can make the end of a campaign more fulfilling. First, let the group finish out their roleplaying in the final moments of the adventure until they're content. Then tell the group the results of what they accomplished in broad terms, with concrete details of what happens to certain places or allied NPCs. Ask the players what their characters do after the adventure. You might want to narrate a few short scenes. When your epilogue is done, thank everyone for playing. If the campaign ended in success for the PCs, give yourselves a round of applause. A victorious ending warrants celebration!

One of your most important and rewarding tasks is getting to know your players and what makes them tick, then implementing plot hooks that speak to their motivations. If your players all like similar things (maybe they all like epic storylines or all prefer tactical combat), your job will be a bit easier. For most groups, there's a mix of preferences and playstyles, and you'll want to put in a few detailed NPCs who appeal to one player's love of social scenes, a powerful villain or looming disaster to engage a player who loves stories of winning against overwhelming odds, and cute alien creatures that attract a player who's into having animal friends. If you're not sure what your players enjoy, ask them in advance what they'd like to see in the game!

Considering player motivations doesn't mean assuming you know what the players or their characters will do! It can be risky to expect PCs to react in certain ways or take certain paths. Knowing their motivations gives you a way to put in elements you expect will appeal to your players, but their decisions will still take the adventure in unexpected directions. You can try to think ahead when playing your sessions, but it's impossible to know how players will react in every imagined situation, or even how you might present the material that day. The important thing is getting the players engaged, not predicting the future.

Think about the emotional and thematic touchstones you want to hit during play. Good games elicit strong emotions, and planning for them can give an emotional arc to an adventure in addition to the narrative arc. Consider what you want players to feel as they play. Is it triumph? Dread? Sadness? Optimism? None of these will be the only emotions to come out, but they'll inform how you build the settings and NPCs. Adventure Recipes gives steps to effectively implement theme and feeling.

You can give players variety through the types of challenges the group faces (combat, social, problem-solving, and so on), the locations they explore, the NPCs they meet, the monsters they face, and the treasure they acquire. Even if you're building an enclosed “dungeon,” or complex like a cramped space station or enclosed building, you don't want to place a combat in every room, or exploration will quickly become stale.

Think in terms of sessions. If your group gets through five scenes per session, how do you make one game session feel different from another? Maybe two of the scenes in each are fairly basic combat encounters, but if you make the other scenes significantly different, or even if you set the encounters in different environments, the sessions won't feel repetitive. Also think about the tools used to solve each situation. Maybe one requires complex negotiations, another brute force, and a third sneaking about. Aim to give everybody something compelling, and ideally targeted at their motivations and abilities.

These procedures help you build an adventure skeleton or outline. You'll then go through and flesh out the details of the adventure, including adversaries and locations. As you play, you'll keep adjusting to fit the events of the game. Anything you haven't already introduced can be changed as needed. Just like with any recipe, you're meant to adjust the details to fit your group's preferences. You might stray far from your starting point, and that's OK!

These recipes use eight steps. You might want to look ahead to your future steps and make choices out of order based on what's most important for you to convey. The catch-all term “opposition” refers to the various adversaries and obstacles the PCs will face. The opposition should be thematically consistent but not necessarily monolithic. It might contain multiple individuals or groups who might not get along with one another.

• Styles: The overall vibe of your game, such as exploration, dystopian adventure, horror, infiltration, intrigue, military adventure, mystery, planar adventure, romantic adventure, or space opera. These frameworks offer guidelines for the number of sessions and types of encounters that work best.
• Threats: Thematic dangers to incorporate into your game, and ways to evoke them as you play. The style and threat are the core parts of your recipe.
• Motivations: Determine more specifically what the opposition's goals and motivations are.
• Story Arcs: This section gives you guidance on how to construct story arcs that will play out over your adventure and maybe beyond.
• NPCs and Organizations: The characters and factions you include should fit the theme.
• Locations: The adventuring sites and settlements featured in your adventure.
• Encounters: The individual rooms and locales within your adventuring sites, including the creatures and hazards found at these places.
• Treasure: The rewards you give out to characters after dealing with encounters.

The most common type of encounter is a combat encounter, where the PCs face other creatures. Combat encounters are strictly governed by rules; the guidelines that follow will help you build combat encounters that pose appropriate challenges for your group. Building hazard encounters works the same way.

To build a combat encounter, first decide how the encounter fits in the adventure as a whole. Then, estimate how much of a threat you want the encounter to pose, using one of five categories below.

Trivial-threat encounters are so easy that the characters have essentially no chance of losing. They're unlikely to spend significant resources unless they're particularly wasteful. These encounters work best as warm-ups, palate cleansers, or reminders of how awesome the characters are. A trivial-threat encounter can still be fun to play, so don't ignore them just because of the lack of challenge.

Low-threat encounters present a veneer of difficulty and typically use some of the party's resources. However, it would be rare or the result of very poor tactics for the entire party to be seriously endangered.

Moderate-threat encounters are a serious challenge to the characters, though unlikely to overpower them completely. Characters usually need to use sound tactics and manage their resources wisely to come out of a moderate-threat encounter ready to continue on and face a harder challenge without resting.

Severe-threat encounters are the hardest encounters most groups of characters have a good chance to defeat. These encounters are appropriate for important moments in your story, such as confronting a final boss. Use severe encounters carefully—there's a good chance a character could die, and a small chance the whole group could. Bad luck, poor tactics, or a lack of resources can easily turn a severe-threat encounter against the characters, and a wise group keeps the option to disengage open.

Extreme-threat encounters are so dangerous that they're likely to be an even match for the characters, particularly if the characters are low on resources. This makes them too challenging for most uses! Use an extreme encounter only if you're willing to take the chance the entire party will die. An extreme-threat encounter might be appropriate for a fully rested group of characters that can go all-out, for the climactic encounter at the end of an entire campaign, or for a group of veteran players using advanced tactics and teamwork.

Variety in encounters is essential to let players try new tactics and give different PCs chances to shine as they face foes with weak points they're uniquely suited to exploiting. Consider the following forms of encounter variety.

• Theme: Look for ways to include varied creatures and locations. Even if the PCs are fighting the undead privateers of the Corpse Fleet, they should encounter other creatures, too!
• Difficulty: A string of moderate-threat encounters can feel flat. Use low- and even trivial-threat encounters to give PCs chances to really shine, and severe-threat encounters for especially powerful enemies. Extreme-threat encounters should be used sparingly for enemies who match the threat posed by the PCs and have a solid chance of beating them! The adventure recipes on page 68 include a mix of combat difficulties that can be useful to look at.
• Complexity: Many encounters should be simple. Save complexity for important or memorable fights.
• Encounter Composition: The number of creatures per encounter and their levels should vary. Higher-level single enemies, squads of enemies, and large numbers of lackeys all feel different.
• Setup: Not all encounters should start and end the same way. PCs might sneak up on unprepared enemies, get ambushed by foes hunting them, enter into a formal duel, or find a diplomatic overture fails and turns into a fight. On the other side, enemies might all be taken out, retreat, beg for mercy, or even shift the encounter to a chase or transform into another phase.
• Terrain: Encounters should account for different types of movement and ranged weapons. Elevation can increase range in close quarters. Adding a hazard, cover, or other terrain features changes a combat and can make a familiar map feel dynamic.

Choose compelling settings for your encounters. When encounters take place in a building or space station, the most significant environmental features originate from the occupants, both past and present. Think about their tastes, biology, or wealth. These features could be natural, such as the sickening decay of partially frozen prey in the snow cave of a predator. They could also be chemical, such as a cloud of poisonous gas, or magical, such as a strange electric current that arcs between a computer console and the walls and occasionally leaps out at passersby.

In some cases, you'll have a location in which an enemy always appears, and you can design your location to suit that specific creature. Other times, an encounter might appear in a variety of places, such as a security guard or wandering driftdead. In these cases, you'll need several terrain and structure options so there's something interesting about the environment no matter where the battle takes place.

Every encounter should happen for a reason. Consider a creature's motivation to fight. Is it defending its home? Robbing to enrich itself? Following sadistic impulses? Simply being paid to fight? You might realize a creature doesn't have a compelling motivation or that the PCs have done something that eliminates the impetus to fight. In that case, the encounter doesn't need to happen! Your game might be more satisfying if the PCs' clever actions avoid the fight—provided you award them XP accordingly.

While you can certainly create enjoyable encounters by placing a group of opponents in a square room with little else, you have numerous tools to create encounters that are more interactive and dynamic. These tools can challenge your players to invent new strategies, inspire interesting character decisions, and make your setting richer.

No encounter needs to use all of the elements presented here, and not all encounters need more than one or two. The more complex a dynamic encounter is, the longer it takes to run and the more demanding it is. In general, these tools are perfectly suited for boss encounters, for memorable foes, and as a spice to add throughout your campaign however often works best for you and your players.

Details on how to run a social encounter, and the differences between a social and combat encounter, appear under Social Encounters. The setup for a social encounter tends to be less detailed. For the NPCs involved, you'll just need statistics for their social skills, Perception, and Will. These use the non-combat level of the creature, based on the creature's social skills, not its combat level. You determine the challenge of a social encounter based on this non-combat level.

You also need to decide the objective or consequences of the social encounter—what the PCs can achieve and what happens if they fail—and the form of the challenge. It might be an online debate, a private meeting with a powerful person, or some kind of contest. Just like with combat encounters, think about the environment, with a particular eye toward the other people around. Is there a moderator the PCs can sway? Are they in an expensive private room in the hottest nightclub or at a crowded coffee shop? Is the atmosphere oppressive? Hopeful?

You might find the PCs' goals end up being quite different from what you initially thought they would be. Fortunately, social encounters are adaptable. Thinking of their likely objective helps you construct the scene in your mind more easily but shouldn't limit you.

The standard rules count treasure over the course of a level, rather than dividing it up by encounter. If you need to select treasure for a single encounter, such as in a sandbox game, you can use the table above. It takes the treasure budget for each level and breaks that down per encounter based on the encounter threat, similar to how XP varies by threat. The final column shows extra treasure you should award if you build an entire level this way. Unlike the standard table, this doesn't include items by item level, as the value doesn't cleanly break down for most single encounters. It's recommended you still give out those permanent items, but you'll need to borrow from other encounters' treasure to account for their value. Include encounters against creatures without treasure to account for this.

If you're not sure about a variant rule, take a chance! Make sure everyone in your group understands that this is a trial run and that you might need to adjust or remove the variant rules later on if they're causing unexpected side effects or not working as you intended. When you're playing with variant rules, be sure to let any new players who join the group know about the variant rules your group has chosen. This helps them set their expectations, which is important for making sure there's a feeling of fairness among your players.

If your group is playing a game with themes that call for it, you might wind up combining multiple variant rules together, possibly applying several options at the same time. For instance, in a gritty, hard science fiction or survival-horror game, you might start the PCs as 0-level characters and alter the proficiency bonus progression to remove level at the same time. In general, the variant options in this chapter are sufficiently self-contained, with explanations of how they change the game, that you should be able to combine them without trouble. When you design your own variant rules, be on the lookout for places where new rules might have unexpected overlapping effects on each other and the game.

This variant removes the item bonus to rolls and DCs usually provided by magic and higher-grade tech items (with the exception of armor's item bonus) and replaces it with a new kind of bonus—potency—to reflect a character's innate ability. In this variant, magic items, if they exist at all, can provide unique special abilities rather than numerical increases.

Sometimes the story of your game calls for a group where everyone is a space pirate or an apprentice at a cosmonastery. The free archetype variant introduces a shared aspect to every character without taking away any of that character's existing choices.

Before they were heroes, every PC came from somewhere, whether they poured coffee in a dusty, sun-scoured village like Chk Chk or performed in a busy spaceport like Dae. Sometimes, it can be a lot of fun to play a prequel game set years before the PCs' first adventure as heroes, or you might have an idea for a low-powered adventure. The rules below provide ways to build and use level 0 PCs.

This variant removes a character's level from their proficiency bonus, scaling it differently for a style of game that's outside the norm. This is a significant change to the system. The proficiency rank progression in Player Core is designed for science-fantasy games where heroes rise from humble origins to legendary strength. For some games, this narrative arc doesn't fit. Such games are about hedging bets in an uncertain and gritty world, in which even the world's best soldier can't guarantee a win against a large group of moderately skilled mercenaries.

The initial implementation is fairly straightforward: the proficiency bonus just becomes +2 for trained, +4 for expert, +6 for master, and +8 for legendary. It's best to give an untrained character a –2 proficiency modifier instead of a +0 proficiency bonus.

Additionally, for creatures, hazards, magic items, and so on, reduce each statistic that would include a proficiency bonus by the level of the creature or other rules element. These statistics are typically modifiers and DCs for attacks, ACs, saving throws, Perception, skills, and spells.

Finally, decrease the skill DCs of most tasks. You can just subtract the level from the DC tables, or you can reference the Simple Skill DCs (No Level) table for a set of DCs that's easier to remember. The new DCs make it a little harder for high-level characters to succeed than it would be when using the default numbers, in keeping with the theme mentioned earlier. Combat outcomes will tend to flatten out, with critical successes and critical failures being less likely across the game. This is particularly notable in spells, where you're less likely to see the extreme effects of critical failures on saves.

• Ancestry Paragon provides more ancestry feats to help further differentiate characters using Starfinder's diverse array of species.
• Expanded Space Rules gives guidelines for adding additional rules when playing in zero gravity and a vacuum.
• Galactic Hero Points provides a simple adjustment to make Hero Points more heroic.
• Skill Paragon provides additional skill feats for a specific skill to help highlight the themes of the character and campaign.

Many characters have some elements that connect them to their ancestry but identify more strongly with their class or unique personality. Sometimes, though, a character is the embodiment of their ancestry to the point that it's of equal importance to their class. For a game where an ancestral background is a major theme and such characters are the norm, your group might consider using the ancestry paragon variant.

This set of variant rules provides a more realistic approximation of some of the stranger phenomena concerning zero gravity and vacuum environments. They're meant to supplement the existing rules, not replace them. You can apply any or all of them to your campaign, as each adds additional challenges and opportunities for memorable moments in space!

These rules add additional complications to an already logistically complex environment. Therefore, you should only use these variant rules if you plan on having multiple encounters in space. Make sure the first couple of encounters in zero gravity are simple in execution and trivial in difficulty so players can get used to the additional rules and understand them before you add additional complexities like creatures who use special abilities to exploit the environment.

Hero Points are a powerful resource that can change the course of a scene via a key reroll. However, sometimes the use of Hero Points can become underwhelming when the reroll result is worse than the initial result—it might even feel worse if the reroll result is the same result as the original roll! This simple variant rule is intended to make Hero Points more of a heroic resource in your campaign, allowing you to reroll low results into something better. Using this rule will increase the overall power of Hero Points and, like some other variant rules, is something you'll want to heavily consider the ramifications of before including in your game.

Skill feats allow characters to gain thematic feats that can help them in exploration, downtime, and social interactions. But given the high stakes of encounter mode, many players feel pressured to select skill feats that improve their efficacy in combat at the expense of selecting feats that better represent their character's abilities. This can be especially frustrating if a character wants to specialize in a skill like Diplomacy or Piloting that includes skill feats that might only see use in one or two sessions.

A curse is a manifestation of potent ill will. Curses typically have a single effect that takes place upon a failed saving throw and lasts a specified amount of time, or can be removed only by certain actions a character must perform or conditions they must meet. Rarely, curses will have stages; these follow the rules for afflictions.

Curses may come from a malicious action, such as a necrovite's Painful Mark or a spell from an otherworldly spellcaster. The guardians of an orbital tomb or of the remnants of a destroyed world might ward their charge with a curse as protection against scavengers. Gods may inflict curses on servants who have raised their ire. In some rare cases, a curse might manifest as a response to a terrible act, such as the wanton destruction of natural resources or a massacre. When using a curse in your game, assign the curse to an item, location, situation, or similar element. Then, decide on a trigger for the curse—such as a creature attempting to steal a unique datapad, destroy a work of art, or slay a specific creature. A curse can even be tied to a specific location, in which case it functions as a simple hazard. Once that trigger occurs, the curse affects the triggering creature or creatures. Each affected creature must attempt a saving throw against the curse; if they fail, they are subject to the effects specified in the curse's Effect entry.

Exposure to disease can be a hazard, such as when PCs come into contact with a Stardust plague-ridden corpse. Such hazards grant XP as a simple hazard of the disease's level. When a disease gives a sickened condition that can't be reduced until it runs its course, that typically means the disease has symptoms such as difficulty swallowing, loss of appetite, or nausea that make eating and drinking difficult but not impossible. Despite the condition's prohibition on eating or drinking, a creature can slowly and carefully eat and drink as long as they aren't in an encounter.

Some environmental features or natural disasters deal damage. Because the amount of damage can vary based on the specific circumstances, the rules for specific environments and natural disasters use damage categories to describe the damage, rather than exact numbers. Use the Environmental Damage table to determine damage from an environment or natural disaster. When deciding the exact damage amount, use your best judgment based on how extreme you deem the danger to be.

Aquatic environments are among the most challenging for PCs short of other worlds and unusual planes. PCs in an aquatic environment need a way to breathe (typically a water breathing spell) and must usually Swim to move, though a PC who sinks to the bottom can walk awkwardly, using the rules for greater difficult terrain. Characters in aquatic environments make frequent use of the rules for aquatic combat and the drowning and suffocation rules.

The main challenge in an arctic environment is the extreme low temperature, but arctic environments also contain ice and snow. The disasters that most often strike in arctic environments are avalanches, blizzards, and floods.

Desert encompasses sandy and rocky deserts as well as badlands. Though tundra is technically a desert, it's classified as arctic, as the climate is the primary challenge in such areas. Sandy deserts often have quicksand and sandstorms.

These diverse environments include jungles and other wooded areas. They're sometimes struck by wildfires.

Mountain environments also include hills. The most common disasters here are avalanches.

Wetlands are the most common kind of swamp, but this category also includes drier marshes such as moors. Swamps often contain quicksand. Despite their soggy nature, swamps aren't likely to experience flooding since they act as natural sponges and absorb a great deal of water before they flood.

Underground environments consist of caves and natural subterranean areas. Artificial dungeons and ruins combine underground features with urban features like stairs and walls. Deep underground vaults have some of the same terrain features as mountains, such as chasms and cliffs. The most common disasters underground are collapses.

Urban environments include open city spaces and buildings as well as the interiors of constructed environments and structures, including climate-controlled satellite cities, orbital stations, and starship interiors. The building information in this section also applies to ruins and constructed dungeons. Depending on their construction and location, cities might be vulnerable to many sorts of disasters, especially fires and floods, while the interior of starships and space stations are more likely to be vulnerable to decompression and power outages.

Weird environments are unpredictable and erratic. Weird environments are often found on irregular planets or places scarred by powerful magic or other strange phenomena. A weird environment might be a patchwork of disparate ecosystems, with a lava field inexplicably bordering arctic tundra, or a bizarre biome such as a shallow, luminescent sea afloat with psychic jellyfish exhaling their emotions in jets of color and sensation. Psystorms and radiation are examples of threats that might be encountered in weird environments.

Outer space holds countless stars, planets, and other cosmic bodies. Most characters will venture into space during their adventuring career. Shuttling between planets, visiting an orbiting space station, or traveling to a distant star system are examples of common travel that require a journey through outer space. Most travelers embark on such trips aboard a starship, which protects them from outer space's environmental dangers.

An atmosphere is a layer of gases held in place by a planet's gravity. There are various types, and some are hazardous.

Weather is more than just set dressing to establish mood—it has mechanical effects you can combine with environmental components to create a more memorable encounter. Weather can impose circumstance penalties on certain checks, from –1 to –4 based on severity.

Most habitable planets have gravity similar to Earth or the world of Lost Golarion, defined as normal gravity. Other environments have higher or lower gravity, potentially debilitating characters or empowering them like superheroes.

Radiation is a threat to adventurers, whether it's the radiation emitted from stars or the radiation generated by various technological wonders of the universe.

Climate and environmental features can be a hindrance or long-term threat, but natural disasters represent acute danger, especially to those directly exposed to their fury.

Every hazard has a trigger of some kind that sets its dangers in motion. For traps, this could be a mechanism like a trip wire or a pressure plate, while for an environmental hazard or haunt, the trigger might simply be proximity. When characters approach a hazard, they have a chance of finding the trigger area or mechanism before triggering the hazard. They automatically receive a check to detect hazards unless the hazards require a minimum proficiency rank to do so.

During exploration, determine whether the party detects a hazard when the PCs first enter the general area in which it appears. If the hazard doesn't list a minimum proficiency rank, roll a secret Perception check against the hazard's Stealth DC for each PC. For hazards with a minimum proficiency rank, roll only if someone is actively searching (using the Search activity while exploring or the Seek action in an encounter), and only if they have the listed proficiency rank or higher. Anyone who succeeds becomes aware of the hazard, and you describe what they notice.

Magical hazards that don't have a minimum proficiency rank listed can be found using detect magic, but this spell doesn't provide enough information to understand or disable the hazard—it only reveals the hazard's presence. Determining a magical hazard's properties thoroughly enough to disable it requires either the use of more powerful magic or a successful skill check, likely using Identify Magic or Recall Knowledge. Magical hazards with a minimum proficiency rank can't be found with detect magic at all.

If the group fails to detect a hazard and the hazard's trigger is a standard part of traveling (such as stepping on a floor plate or moving through a motion sensor while walking), the hazard's reaction occurs. Hazards that would be triggered only when someone directly manipulates the environment—by opening a door or touching a control panel, for example—use their reactions only if a PC explicitly takes that action.

The most versatile method for deactivating traps is the Disable a Device action of the Thievery skill, though many mechanical and technological traps can also simply be smashed, and magical traps can usually be counteracted. Sometimes, mechanical or technological traps can also be deactivated with Computers or Crafting. Environmental hazards often can be overcome with Nature or Survival, and haunts can often be overcome with Occultism or Religion. The specific skill and DC required to disable a hazard are listed in the hazard's stat block. Like using Disable a Device, using these skills to disable a trap is a 2-action activity with the same degrees of success, though the activity might have different traits determined by the GM. As with detecting a hazard, disabling a hazard might require a character to have a certain proficiency rank in the listed skill.

A character must first detect a hazard (or have it pointed out to them) to try to deactivate it. They can attempt to deactivate a hazard whether or not it has already been triggered, though some hazards no longer pose a danger once their reactions have occurred, especially if there's no way for them to be reset.

For most hazards, a successful check for the listed skill against the DC in the stat block disables the hazard without triggering it. Any other means of deactivating the hazard are included in the hazard's stat block, as are any additional steps required to properly deactivate it. A critical failure on any roll to disable a hazard triggers it, including a critical failure on a roll to counteract a magical hazard.

Some hazards require multiple successful checks to deactivate, typically because they have a particularly complicated component or have several discrete portions. For hazards with a complex component, a critical success on a check to disable the hazard counts as two successes on a single component.

Characters gain Experience Points for overcoming a hazard, whether they disable it, avoid it, or simply endure its attacks. If they trigger the same hazard later on, they don't gain XP for the hazard again. The XP values for hazards of different levels also appear in XP Rewards but are repeated here for convenience. The XP for a complex hazard is equal to the XP for a monster of the same level, and the XP for a simple hazard is one-fifth of that. Hazards of a lower level than the party's level – 4 are trivial and award no XP.

Hazards are presented in a stat block format similar to those used for monsters. A few notes regarding the format follow the sample stat block.

Hazard NameHazard Level

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Traits
Stealth This entry lists the Stealth modifier for a complex hazard's initiative or the Stealth DC to detect a simple hazard, followed by the minimum proficiency rank to detect the hazard (if any) in parentheses. If detect magic can be used to detect the hazard, this information is located here as well.
Description This explains what the hazard looks like and might include special rules.

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Disable The DC of any skill checks required to disable the hazard are here; if the hazard can be counteracted, its spell rank and counteract DC are listed in parentheses.
AC the hazard's AC; Saving Throws the hazard's saves. Usually only haunts are subject to Will saves.
Hardness the hazard's Hardness; HP the hazard's Hit Points, with its Broken Threshold in parentheses; Immunities the hazard's immunities; Weaknesses the hazard's weaknesses, if any; Resistances the hazard's resistances, if any
Action Type [reaction] or [free-action] This is the reaction or free action the hazard uses; Trigger The trigger that sets off the hazard appears here; Effect For a simple hazard, this effect is often all the hazard does. For a complex hazard, this might also cause the hazard to roll initiative.
Routine This entry describes what a complex hazard does on each of its turns during an encounter; the number in parentheses after the word “Routine” indicates how many actions the hazard can use each turn. Simple hazards don't have this entry.
Action Any action the hazard can use appears here. Typically, this is a melee or ranged Strike.

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Reset If the hazard can be reset, that information is here.

A simple hazard uses its reaction only once, after which its threat is over unless the hazard is reset.

Complex hazards function similarly to monsters during encounters, as they roll initiative and have actions of their own, though these are usually automated in a routine. Complex hazards can be used in encounters to take the place of a creature of the same level and are worth XP.

The first thing you'll need is a concept for your hazard. What level is your hazard? Will it be simple or complex? Is it a trap, a haunt, an environmental hazard, or something else? If it's a trap, is it mechanical, magical, tech, or all of the above? This is a good time to consider the hazard's description and how to disable it.

Statistics determine how your hazard interacts with the game world, representing how dangerous it is and how hard it is to render harmless or circumvent. The statistics for your hazard can have extreme, high, or low values. You'll want to choose the value that's most appropriate for the concept of your hazard while ensuring that it's well balanced to ensure a fun encounter.

Extreme: The hazard is world-class in this statistic and can challenge almost any character. Almost all hazards have one extreme statistic because hazards normally activate only if they've gone unnoticed or if someone critically failed to disable them. Does it have an extreme Stealth DC that makes it incredibly hard to find, an extreme Disable DC that makes it perilous to disable, or an extreme save DC that makes it deadly in the event it triggers? These are the most common choices, as each affects a different phase of encountering the hazard.

High: Extremely capable but not world-class, the hazard presents a challenge for most characters. This is a capable level and can generally serve as a baseline value.

Low: If a hazard has a weakness, like a poor Reflex save for a bulky mechanical trap or an easy DC to disable for a hard-to-find trap, it usually has a low value. If you need something even lower, use a terrible value from Building Creatures, or just an incredibly low value.

When determining a hazard's combat statistics, first decide how the hazard can be located and how hard it is to disable. A hazard where the main challenge is how difficult it is to find, like memory crystals, might have a very different effect for its level than a hazard out in plain sight, daring a PC to try to disable it, like the laser turret or the monument to the Devourer.

When deciding how your hazard is disabled, come up with a narrative description of how it would happen, which will inform which methods and skills disable the hazard. You'll need to decide the proficiency rank necessary to find the hazard as well as disable it with each method. Remember, a hazard without a listed rank next to its Stealth DC is obvious enough that creatures can find it without Searching, and magical hazards without a listed rank aren't normally protected against detect magic. Most hazards built by intelligent creatures are concealed and have at least a trained rank. The Minimum Proficiency table indicates the high and moderate proficiency requirements by level; you can use lower proficiency ranks than the ones listed, and if you use the high rank, consider a secondary, perhaps less-efficient method to disable the hazard using a lower rank. For instance, the exploding egg sac environmental hazard can be disabled with expert Survival, or by a higher DC with trained Nature.

If you need a Stealth modifier for a complex hazard, just subtract 10 from the listed DC.

If there's a physical component that a character could break, you'll need to determine the hazard's AC, Fortitude save, and Reflex save, using the extreme, high, and low values (preceded by E, H, or L on the Hazard Defenses table) as well as its Hardness, HP, and Broken Threshold (BT). When building a purely magical or formless hazard, you can skip this section.

Some hazards, even high-level ones, don't make sense with a high Hardness value. In those cases, you can skip the Hardness and use the HP values from the Hit Points table. Especially for complex hazards, you might want to divide the durability over multiple sections, located in different positions, to encourage teamwork and mobility.

Almost all hazards need an attack bonus or a save DC, and hazards that deal damage need to list a damage value. Simple hazards deal about twice as much damage as complex hazards and have a very high attack bonus (abbreviated as S. Atk in the Hazard Offense table on page 115). Complex hazards usually have more moderate attack bonuses (abbreviated as C. Atk in the table). You can adjust them further using the Strike Attack Bonus table on page 124 if your hazard needs it. Simple hazard DCs aren't as high for their level as their attack bonuses are since effects with DCs usually have some effect even on a successful saving throw; use the EDC and HDC columns for extreme and hard DCs in the table.

The damage columns on the table give a damage expression you can use, followed by the average damage in parentheses. If you want to make your own damage expression, remember that average damage is 2.5 for a d4, 3.5 for a d6, 4.5 for a d8, 5.5 for a d10, and 6.5 for a d12.

When designing a simple hazard, make sure to select an appropriate trigger and effect. Often, a simple hazard that merely damages its target is little more than a speed bump that slows down the game without much added value, so think about the purpose of your hazard carefully, both in the story and in the game world, especially when it's a hazard that a creature intentionally built or placed in that location. A great simple hazard does something interesting, has a longer-lasting consequence, or integrates with the nearby inhabitants or encounters in some way (as discussed under Dynamic Encounters).

Unlike a simple hazard, a complex hazard can play the part of a creature in a battle or can be an encounter all its own. Many of the concerns with damaging effects when designing a simple hazard don't apply when designing a complex hazard. A complex hazard can deal its damage over and over again and isn't intended to be quick to overcome.

A good complex hazard often requires disabling multiple components or otherwise interacting with the encounter in some way. For instance, while the haywire autopilot can be remotely reprogrammed with a challenging Computers check, characters who want to use Piloting or Thievery to override the autopilot will first need to board the vehicle using Acrobatics or Athletics.

To begin, come up with the creature's concept. You likely already have the basic idea. As you add details to the general idea, taking notes can help keep your creature on track. Consider the parts of your creature you find most compelling and want to emphasize when the creature hits the table. For example, in Alien Core, typodaemons thrive on the subtle destruction wrought by their mischief and become sickened if you point out their intentional errors. Tax collector robots relentlessly pursue their targets but can be placated by paying a fine, as represented by their centerpiece ability, tax collector. Note your creature's core aspects, and if you feel uncertain later, you can look back and ask yourself, “Does this emphasize a core aspect or not?”

Next, look at the creature's role in your game. Is it meant to be a combatant? A social creature? A trusted ally? Figuring this out will help you determine whether to give it strong combat abilities or to focus on skills, spells, and special abilities. Think about how the creature might behave if it's in a fight, if someone tries to talk to it, or if it's in a social situation. Does it work better alone or with allies? What sort of character should be best at facing it or be particularly weak against it?

Also consider the complexity of the creature. This matters most when you plan to use a large number of creatures of that type. If you'll use five at the same time, you'll want their turns to move swiftly and avoid complex special actions. A creature that's likely to face a group of PCs alone can have more abilities, and it might need a more versatile set of defenses against PC tactics. Cut complexity as much as you can while retaining your desired theme.

Now, how do you want an encounter with this creature to feel? Should it be scary? Mobile? Confusing? A mystical duel or a knockdown, drag-out fight? What can you give your creature to convey those characteristics? Much of this feel will come from your choice of the creature's special abilities or spells, rather than its raw numbers.

With all this in mind, think about what specific abilities your creature should have. Take a few notes now, and get to the details later. You can use abilities from Alien Core or feats in Player Core, adjusting as needed, to save yourself time. It helps to think of a creature that's similar to yours and see what makes it tick—and what you can steal from it. Maybe you can just reskin that creature (sidebar Reskinning a Creature), instead of making a new one from scratch.

Now that you understand your creature's concept, it's time to get to the statistics. Remember that you can always change your concept later on. Your creation might evolve and transform as you go, so be open to change.

Most of the statistics in this section use a scale of extreme, high, moderate, and low—some use terrible values as well.

Extreme: The creature is world-class in this statistic and can challenge almost any character. Most creatures have no extreme statistics or only one extreme statistic, although some creatures might have additional extreme statistics and weaker related statistics elsewhere (a common example being a creature trading accuracy for extreme damage). Examples from Alien Core include the zitteroc's Athletics modifier and the necrovite's spell DC.

High: Extremely capable but not world-class, the creature presents a challenge for most characters. Just about all creatures have at least one high value. Most combat-focused creatures have high AC and either a high attack bonus and high damage, or a merely moderate attack bonus but extreme damage. A cerebinite's attack bonus and a heliad nymph's Diplomacy modifier are high values.

Moderate: A middle-of-the road statistic covers anything unremarkable about the creature. Use this one often.

Low: The creature is actively bad at this. Choose these intentionally to represent the creature's weak points. Most creatures should have at least one low statistic; an example is the warp troll's Will save.

Terrible: Some statistics can dip even lower than low, to terrible. This indicates a truly awful statistic that still isn't game-breakingly bad. A tech zombie's Intelligence is terrible, as is a void ooze's Reflex save.

For most creatures you build, their level depends on the level of the party that will encounter it. Look at other creatures you think are similar in power to yours to determine its level. Note that level represents a creature's combat ability, so a creature that's more social might have 3rd-level combat statistics and 6th-level skills, but it would remain a 3rd-level creature. Most such creatures are NPCs; for more information on this distinction and how to use it, see Non-Combat Level.

Some abilities are hard for PCs to deal with at low levels. For instance, creatures with an extreme AC at lower levels can make for frustrating foes that require exceptionally high rolls to hit. Natural invisibility or at-will invisibility as an innate spell should come at around 6th level, when PCs are more likely to prepare see the unseen in lower-rank spell slots, or 8th level, when some PCs get access to the truesight sight.

The tables in this chapter go up to 24th level, the highest-level extreme encounter a party might face.

Fill out the trait line of your creature's stat block. Creatures can be whatever size you need them to be, though you seldom find Large creatures below 1st level, Huge creatures below 5th level, or Gargantuan creatures below 10th level. Generally, you don't automatically adjust statistics for size, except to Strength modifiers for Large and bigger creatures, which you'll find in the following Attribute Modifiers section.

Your creature will almost certainly have one of the following traits to define its type: aberration, animal, astral, beast, celestial, construct, dragon, elemental, ethereal, fey, fiend, fungus, giant, humanoid, monitor, ooze, plant, robot, or undead. If you're making a creature from an existing category of a type, such as demon, it also has that category as a trait. Creatures with a close affinity to elements—air, earth, fire, metal, water and wood—or types of energy—like acid, cold, and electricity—have those traits.

Some abilities that are typical of creatures with the traits listed here can be found in Trait Abilities. As with the other steps, looking at similar creatures will give you an idea of what traits to use.

Add any traits that have detailed rules attached to them, like amphibious, aquatic, cosmic, incorporeal, mindless, and swarm. You can add traits related to the creature category, such as kucharn or midwife, but most of these traits are pretty self-evident in play. If at any point you realize during play that you didn't add a trait the creature really should have, you can usually apply it retroactively.

Next, figure out your creature's attribute modifiers since these will suggest what their other statistics should be. You don't have to determine the exact numbers, but it's good to avoid creating creatures whose attribute modifiers are at odds with their abilities, like creatures with a terrible Wisdom modifier and a very high Perception. Most of the time, you'll just be using attribute modifiers for untrained skills, so they're useful as a guide but not crucial.

The Attribute Modifier Scales table shows some benchmarks for your creatures. Use high for the creature's best attribute modifiers, moderate for ones they're okay at, and low for the rest. If a creature has a truly bad ability, you can go as low as –5. That's the terrible range for attribute modifiers, and doesn't really change by level. This is most common with animals, which have an Intelligence modifier of –4 (for khefaks, laser wolves, rats, and such) or –5 (for more instinctual animals like insects), and for mindless creatures, which have a –5 Intelligence modifier.

Few creatures use the extreme column. A powerful, dedicated spellcaster might use an extreme spellcasting statistic, or a preternaturally charming creature like a nymph might have an extreme Charisma modifier. However, the most common way extreme numbers are used is for really big, really strong creatures. This happens with only Large or bigger creatures from 1st to 5th level, Huge or larger creatures from 6th to 9th level, and Gargantuan creatures from 10th to 15th level. Beyond that level, a creature doesn't gain an extreme Strength modifier from size alone.

Perception is a fairly straightforward statistic. Use Wisdom as a guide for setting it, and adjust to the high side if your creature has acute senses or extra training. If your creature has low Wisdom, for example, it would probably have a low Perception modifier, or moderate if it's supposed to be a great hunter. Don't make your creature's Perception higher just because it's often used for initiative; creatures with poor Perception could use a skill check for initiative instead, such as Stealth.

Think about what languages the creature would need to communicate with other creatures in its home. For instance, many intelligent undead speak Necril, and many creatures from the Azlanti Star Empire speak Azlanti. If you want your creature to be able to speak to the PCs, be sure it has Common; for a creature with no reason to speak the common tongue of your setting (such as most extraplanar creatures in a typical campaign, or creatures from the Vast), be sure it doesn't. Some creatures can understand language but can't vocalize; in this case, you can state that they can't speak any language. For creatures that need to be able to infiltrate and communicate wherever they go, you might give them a digital translator, truespeech, the ability to communicate telepathically, or a similar ability as a constant innate spell.

You have lots of flexibility in setting your creature's skills. Pick some skills you think are appropriate, and consider how good the creature is at them. High skills are roughly on par with a specialized PC of the creature's level, though they could be a little lower or higher. Most creatures have at least one high skill, but no more than three. The best skills should go with the best attribute modifiers, and you might even want to estimate the creature's proficiency rank for these skills. Some skills can get a high bonus for free to fit the creature's theme, particularly Lore skills.

Most creatures don't have an extreme skill unless they're world-class for their level, like a necrovite's Arcana. Having an extreme skill is less impactful than having an extreme AC or attack bonus, but it still might warrant a sacrifice elsewhere, especially if the creature also has more high skills than usual. There's no need for terrible skill modifiers since an untrained skill usually represents that.

If you gave a creature gear equivalent to a PC, your PCs would gain a huge amount of treasure by defeating a large group of them. Using the Safe Items table can help you avoid that. A creature can have a single permanent item of the listed level without issue. For example, if a 6th-level creature has a tactical doshko, that item isn't worth enough that the PCs would be massively rich if they encountered many creatures of that type and sold everything they found. You can give a creature several lower-level items too. Just pay attention to your overall treasure as measured against the Safe Item table on page 121. At the lowest levels, a creature can certainly have multiple level 0 items, even though normally a creature should have only one item of the level listed in the Safe Item Level column. You can also give a creature's item the implanted trait if it's attached to its body, making it so the item can't be looted.

Specific creatures or NPCs have more leeway to break these guidelines because you can plan the rest of your adventure's loot around them. Also, giving a boss a powerful magic item makes the fight and its aftermath more interesting.

Consider adjusting your creature's HP, AC, and saves in tandem based on its theme. Almost no creature has great defenses in all areas, and such creatures often result in frustrating fights. A creature with extreme AC might mean reducing its HP to the next lowest category, or reducing its HP by a smaller amount and making another reduction elsewhere. On the other hand, a creature that's easy to hit could have more HP and a strong Fortitude save to compensate.

Give a creature HP in the moderate range unless its theme strongly suggests it should use another range. Spellcasters, for example, often have low HP. Brutish creatures usually have high HP, compensating with lower AC, weaker saves, fewer tactical options, or other limitations. As mentioned in the Defenses section above, you don't want a creature with extreme AC to have high HP too.

Hit Points are closely tied in with immunities, weaknesses, and resistances, so if your creature has any of those, look at that section before finalizing HP.

If it's highly thematic for a creature to have an immunity, weakness, or resistance, consider adding it. The Resistances and Weaknesses table lists the ranges for weaknesses and resistances by level.

Immunities are generally reserved for creatures made of an unusual substance (like a fire elemental being immune to fire). You can also give an immunity if a creature's biology or construction would logically cause it to be unaffected (like a mindless creature's immunity to mental effects). If the creature should be hard to affect with something but the conditions above aren't true, give it a resistance instead. For instance, most cosmic creatures aren't actually made of ice, so it wouldn't be immune to cold, but its life in space makes it resistant to cold. You'll typically use the lower end of the value on the Resistances and Weaknesses table for a broad resistance that applies to a wide range of effects, like "physical 5 (except silver)" and the higher end for something narrower, like a single damage type. A creature with a resistance, especially a broad resistance or a physical resistance, usually has fewer HP.

Giving your creature a weakness adds flavor to it and greatly rewards effective player tactics once your players identify the weakness. The weakness should apply to one damage type or phenomenon and use the high end of the scale. Creatures typically have at most one weakness. If a creature has a weakness, especially to something common, give it additional HP. The amount of additional HP might depend on how tough the creature should feel if the PCs don't exploit its weakness; a tough creature might have additional HP equal to quadruple the weakness value. A creature with a hard-to-exploit weakness might have additional HP equal to the weakness value or less.

In Starfinder, PCs have access to a wide variety of damage types. A 1st-level character can pack a laser pistol (fire damage), a sonic rifle (sonic damage), or even a neural lash (mental damage). Because of this prevalence of damage type accessibility, resistances and weaknesses can often turn the tide of a battle. Some damage types, like fire or cold, often appear as obvious use cases for resistances and weaknesses. Be sure to vary your creature design to include some that might have mental or sonic resistance as a means of encouraging weapon diversity.

The combination of more HP and a weakness has a different feel from standard HP with resistances. If the creature being an impervious tank really fits its theme, use a resistance with an exception, such as "physical 5 (except silver)." If, however, it makes more sense for normal hits to get through and the creature to simply have great staying power, use more HP and a weakness. Living hardlight and tech zombies are a good example of the difference between these styles. Living hardlight has resistances because they're holograms and hard to hurt. Tech zombies, on the other hand, have more HP and a weakness to slashing damage-they're tougher, but their bodies aren't built to deflect weapon attacks, and slashing attacks can rip them up quickly.

Your creature's Speed should be 25 feet if it moves like a human. Beyond that, you can set the Speed to whatever makes sense. Remember that the creature can move up to triple this number if it spends its whole turn moving, so if you want the PCs to be able to chase the creature, its Speed can be only so high. Most creatures should have a ranged attack, fly Speed, or other way to deal with flying PCs, speedy PCs, and PCs with more efficient actions that let them engage and retreat more easily. This includes creatures converted from Pathfinder, where PCs can only fly at higher levels (see Anachronistic Creatures for more information.)

Creatures can have climb and swim Speeds at any level. While you can give your creature a fly Speed at 1st-level, as most PCs should have ranged options available to them, it's better to wait until around 3rd level (when PCs have enough feats to support those ranged attacks and access to items like jump jets and jet packs) to give your creature a fly Speed if it also has ranged attacks or another way to harry the PCs from a distance indefinitely.

When building your creature's selection of Strikes, use the following sections to set the Strike's attack bonus and damage. Give the attack all the normal traits if it's a weapon; for unarmed attacks or weapons you invent, give whatever traits you feel are appropriate. Note that these traits might influence the damage you give the Strike.

You might want to make sure a creature has an unarmed attack if you think it's likely to get disarmed. Creatures should always have access to a ranged strike; even if most PCs can't fly until they get access to jet packs at 5th level, lower-level PCs might still have access to climb Speeds and limited flight options like jump jets much sooner. Some ancestries give innate flight speed too, so it's possible to have a 1st-level PC flying around the battlefield, which means most creatures do need a ranged option or be in an area where flight mobility is limited. Many parties can also pin down melee-only enemies in a way that makes an encounter trivial if the enemies don't have ranged strikes.

Your creature might have magical abilities that are best represented by spells. If you're making a highly spellcastingthemed creature, give it prepared or spontaneous spells. For a creature that has spells due to its magical nature, especially if that magic isn't its core focus, consider giving it some innate spells instead. How many spells you should give a creature depends on how you expect it to spend its actions in combat. If it's primarily going to be making Strikes, it might not have any spells, or it might just have a few to help it move around better or protect against certain types of magic.

When choosing spells, lean hard into the creature's theme. While many PCs choose spells to cover a wide variety of situations, creatures are more evocative the more focused they are. Consider selecting about three-quarters of the spells based on relevance to the theme and the remainder for other things. However, make sure the spells aren't all the same—selecting instant virus for most of a creature's spell slots doesn't make for a compelling disease-themed creature in the way a diverse selection of disease spells would.

When choosing spells, some won't be very useful if cast at an extremely low rank compared to the creature's level. Most notably, damaging spells drop off in usefulness for a creature that's expected to last only a single fight. A damaging spell 2 ranks below the highest rank a creature of that level can cast is still potentially useful, but beyond that, don't bother. Spells that have the incapacitation trait should be in the highest spell slot if you want the creature to potentially get their full effect against PCs.

In this step, you'll take the ideas for abilities you noted when you developed your concept and design these abilities for your creature. You can look at existing creature abilities from Alien Core and feats from Player Core and use them as is or modify them to fit your needs.

When choosing abilities, think about both the number of abilities and the diversity of abilities. Having a large number of similar abilities can make the creature tougher to run, and it probably can't use them all anyway. A diversity of abilities gives the creature different ways to act in different situations and helps guide you as the GM. For instance, a combat creature might have one ability it uses to get into position, another to use when it wants to focus damage on a single enemy, and a third that's more defensive.

Now it's time to look over your completed creature as a whole and make sure it's living up to your concept. Can it do everything you wanted? Does it fit its intended role? Is there anything you could add or anything superfluous you could cut to get the creature where it needs to be?

If this creature is built for combat, run through a few turns in your head. Does it still work decently if it gets slowed? Can it move into combat against the PCs effectively considering their mobility options compared to its own? Does it have any abilities it'll never use because of its other actions?

When you're satisfied with your creation, it's ready to hit the table. But that's not necessarily the end! If you notice issues during the game, you can fix them on the spot. It's your game, and you can freely change what you wrote if you think differently later on.

Creatures with certain traits tend to have similar abilities to one another. Many of these abilities are listed below to help you match the theme of the trait when you build your own creatures. Look at existing creatures with the trait to see these in practice.

Aberration

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Senses usually darkvision
Languages usually Aklo

Aeon

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Traits monitor
Languages Utopian and other planar languages; envisioning for true aeons (Alien Core)

Air

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Languages usually Sussuran Speed usually has a fly Speed

Angel

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Traits celestial, holy
Aura Angels each have a unique aura based on how they serve as messengers and how they deliver those message.
Speed usually has a fly Speed
Rituals usually angelic messenger (Alien Core)

Animal

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Languages none
Int –4 or –5

Archon

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Traits celestial, holy
Immunities fear
Virtue Ability Archons each represent a specific virtue, like courage or hope, and have a special ability based on the virtue they represent.

Astral

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Senses darkvision

Azata

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Traits celestial, holy
Weaknesses cold iron
Freedom Ability Azatas each represent a specific freedom, like free expression or free love, and have a special ability based on the freedom they represent.

Beast

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Int –3 or higher

Celestial

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Traits holy
Senses darkvision
Languages Empyrean
Saves often a +1 status bonus to all saves vs. magic
Weaknesses unholy
Strikes typically have the holy trait

Cold

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Immunities or Resistances cold

Construct

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Traits Many constructs lack minds and have the mindless trait.
Immunities bleed, death effects, diseased, doomed, drained, fatigued, healing, nonlethal attacks, paralyzed, poison, sickened, spirit, unconscious, vitality, void; if mindless, add mental

Cosmic

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Senses usually darkvision
Speed cosmic creatures with fly Speeds can fly through space and other zero-gravity environments
Immunities usually cold; Resistances cold or void

Daemon

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Traits fiend, unholy
Languages Daemonic, telepathy 100 feet
Immunities death effects
Death Ability Daemons each represent a specific kind of death, like death by disease or starvation, and have a special ability based on the method of death they represent.

Demon

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Traits fiend, unholy
Languages Chthonian, telepathy (usually 100 feet)
HP typically high to account for their multiple weaknesses
Weaknesses cold iron
Sin Vulnerability Demons each represent a specific sin, like envy or wrath, and have a special vulnerability based on the sin they represent. This should be something the PCs can exploit through their actions, which should then deal mental damage to the demon. The amount of damage should be based on how easy the vulnerability is to exploit.
Divine Innate Spells usually 5th-rank translocate and at-will 4th-rank translocate
Rituals usually demonic pact (Alien Core)
Sin Ability Demons also have a special ability based on the sin they represent, which either makes them better embody the sin or instills that sin in others.

Devil

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Traits fiend, unholy
Languages Diabolic, telepathy (usually 100 feet)
Immunities fire; Weaknesses holy; Resistances physical (except silver), poison Divine Innate Spells usually one 5th-rank translocate and at-will 4th-rank translocate
Rituals usually diabolic pact (Alien Core)
Infernal Hierarchy Ability Devils each have an ability corresponding to the role they play in the infernal hierarchy, typically focused around control or being controlled.

Dragon

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Senses darkvision
Languages usually Draconic and Triaxian
Speed usually has a fly Speed
Dragon Breath Many dragons have an activity to exhale magical, damaging energy, with specifics determined by their theme.

Drift

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Traits cosmic

Earth

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Perception often tremorsense
Languages usually Petran
Speed usually a burrow Speed

Elemental

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Senses darkvision
Immunities bleed, paralyzed, poison, sleep

Elindrian

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Senses scent
Languages Elindrian, Formian, telepathy
Husk Mind Elindrians share a telepathic bond that allows them to communicate nearly instantaneously and grants them a primal connection to a massive radioactive ooze known as the Terror of Ukulam.

Ethereal

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Senses darkvision

Fey

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Senses low-light vision
Languages usually Aklo, Fey, or both
Weaknesses cold iron

Fiend

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Traits unholy
Senses darkvision
Saves often a +1 status bonus to all saves vs. magic
Weaknesses holy
Strikes typically have the unholy trait

Fire

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Languages usually Pyric
Immunities fire; Weaknesses typically cold and water
Strikes typically deal fire damage

Fungus

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Traits fungi without minds have the mindless trait
Immunities if mindless, mental; Weaknesses sometimes slashing or fire

Giant

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Traits Large or bigger, humanoid
Senses low-light vision
Languages usually Jotun

Humanoid

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Int –3 or higher

Incorporeal

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Str –5
HP terrible at lower levels, then low at higher levels
AC typically low or moderate
Immunities bleed, disease, paralyzed, poison, precision; Resistances all damage (except force, ghost killer, or spirit; double resistance vs. non-magical) Strikes magical trait, typically low or moderate damage

Jinsul

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Senses all-around vision, darkvision
Languages Jinsul
Strikes leg blades

Kucharn

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Traits Kucharn are colony components, meaning they're in constant telepathic communication with one another because of their hive mind, and each have a specialized function within the Swarm.
Senses darkvision, usually emotionsense

Metal

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Languages usually Talican

Midwife

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Traits aberration, cosmic, midwife, holy or unholy
Languages telepathy (100 feet)
Divine Innate Spellscall cosmos, eldritch lance, eldritch wrath, massacre, revival, slice reality, void vessel; constant detect thoughts

Monitor

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Senses darkvision

Ooze

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Traits Almost all oozes lack minds and have the mindless trait.
Senses typically motion sense and no vision
AC usually terrible
HP usually around double
Immunities bleed, critical hits, precision, unconscious, often acid; if it has no vision, add visual effects; if mindless, add mental

Plant

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Traits plants without minds have the mindless trait
Senses usually low-light vision
Immunities if mindless, mental; Weaknesses sometimes fire

Protean

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Traits monitor
Languages Protean
Resistances precision, protean anatomy (Alien Core)
Divine Innate Spells constant unfettered movement
Change Shape (Alien Core)

Psychopomp

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Traits monitor
Senses lifesense (typically 60 feet)
Languages Requian
Immunities death effects, disease
Resistances poison, void
Damage shepherd's touch (Alien Core)

Spectra

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Traits cosmic, spectra
Languages Trinary, digital telepathy (typically 100 feet), truespeech
Senses darkvision, techsense

Spirit

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Traits often incorporeal, often undead

Swarm

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Traits size based on the entire mass, usually Large or bigger
HP typically low
Immunities grabbed, precision, prone, restrained, swarm mind (Alien Core); Weaknesses area damage, splash damage; Resistances physical, usually with one physical type having lower or no resistance

Undead

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Traits Almost all undead are unholy. Ghostly undead have the incorporeal trait. Undead without minds, such as most zombies, have the mindless trait.
Senses darkvision
HP void healing (Alien Core)
Immunities death effects, disease, paralyzed, poison, sleep (or unconscious if it never rests at all); if mindless, add mental

Water

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Languages usually Thalassic
Speed usually has a swim Speed

Wood

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Languages usually Muan
Weaknesses fire and axes or slashing

Creatures that are meant to cleave closely to character classes or intended to represent people rather than monsters are NPCs. They might face more scrutiny around their mechanics than creatures because a player can more directly compare their operative to an NPC who acts like an operative. That doesn't mean you have to build an NPC exactly like a PC, though.

You can build NPCs just like you would any other creature. If an NPC should work like they have a class, use the class features and feats of a suitable class to pick abilities, and look at both the class's proficiencies and attribute modifiers to determine how strong the NPC's statistics should be. Class Road Maps under PC-Style Build has pre-built road maps for Player Core classes to get you started.

If the NPC isn't meant to work like they have a class (a vidgamer, for example), instead build the character separately. You can create new abilities as needed to get the NPC's interactions with the PCs to express their theme and role in the story. These NPCs can be level –1 or level 0. Their capabilities are below those of PCs, and they should typically not use any class features or feats from PC classes. Creatures of these levels tend to be extremely simple.

It's highly recommended that you select NPC skills using proficiency ranks as you would a PC, though you don't need to be precise about the number of skill increases you give the NPC. You can give them earlier access to expert, master, or legendary proficiency if they're a skill-based NPC and better proficiency in narrow areas of expertise, like Sports Lore for a brutaris player NPC.

First, come up with a concept for the item based on the role the item serves in your game and in the game's world. You might include a new item in an ancient ruin to hint at its history and characterize the technology lost when its creators disappeared. For instance, a ruined starship of the First Ones might have an item related to the construction of anacites, while an abandoned arcology on Bretheda might have medicinal items developed using biohacking technology lost in the Gap.

A new magitech item might be important later in the story, or its role might be as simple as a fun shadow-themed item for the witchwarper that uses Twisted Dark Zone. Keep your concept in mind to guide you through the process. Start thinking about what kind of magic item it will be. Each item type has its own niche, and some are less likely to be as useful to the PCs. For instance, new weapons and armor require the PC to give up the weapon or armor they already have, which might make them more reluctant to use the new items unless they're noticeably better, while consumable items don't have as big an impact on the story as permanent items.

Next, use the item's concept and role to decide its effects. This is where your creativity will bring the item to life. Make sure to have it do something exciting and roleplay-inspiring. An item that does nothing more than deliver a bonus is far less interesting, even if the item does have a load-bearing item bonus, like a tactical-grade weapon. To determine the item's power, take into account the special abilities you give the item as well as the item bonus (if any) that it grants. For specific advice for the type of item you're creating, check out Designing by Type.

The following guidance applies to items of various types.

You're almost done! The final step is to fill in the numbers.

World building can be approached in many ways, but it fundamentally comes down to a simple preference. Do you start at a high level and zoom in, or do you start small and build up? This section outlines a largely top-down approach, but you can design from the bottom up simply by starting at the end of this section and working backward. Either way, you might find yourself skipping between sections as inspiration strikes—and that's OK!

When building worlds, there's a risk of becoming overwhelmed by the sheer number of decisions to be made. Remember that you don't need to make every decision for every aspect of your world all at once. Focus first on the elements you need for your story and the game, then add as much of the rest as you'd like. You'll also want to allow room for input from your players—gaming sessions are more memorable and engaging when the storytelling experience is shared between everyone at the table (Narrative Collaboration has more information on players contributing to the narrative).

Before you decide anything else, however, you should establish your concept and your goals. Do you envision a bustling port of call in Near Space? A star system where magic comes from quarreling regional deities who each control a separate warring planetoid? A low-tech moon unknowingly isolated from the rest of a high-tech system full of starships? Are you designing a whole region of space for a multi-year campaign, or a single settlement on a world for a fast-paced one-shot adventure? Having an idea in mind will help steer your choices as you build your worlds, and knowing your goals will help you focus on building what you need.

Before designing your campaign's first world, you should first consider the nature of its larger system and what that might mean for the planet. While most traditional heliocentric star systems like the Pact Worlds make developing your world as straightforward as taking cues from the real world, other system compositions are possible, either through quirks of physics or the intervention of powerful deities. Other alternatives to traditional heliocentric star systems can be found under Composition of Space.