Ending the Encounter
Source GM Core pg. 33
A combat encounter typically ends when all the creatures on one side are killed or knocked unconscious. Once this happens, you can stop acting in initiative order. The surviving side then has ample time to ensure that everyone taken out stays down. However, you might need to keep using combat rounds if any player characters are near death, clinging to a cliff, or in some other situation where every moment matters for their survival.
You can decide a fight is over if there's no challenge left and the player characters are just cleaning up the last few weak enemies. However, avoid doing this if any of the players still have inventive and interesting things they want to try or spells they're concentrating on—ending an encounter early is a tool to avoid boredom, not to deny someone their fun. You can end a fight early in several ways: the foes can surrender, an adversary can die before its Hit Points run out, or you can simply say the battle is over and that the PCs easily dispatch their remaining foes. In this last case, you might ask, “Is everyone okay if we call the fight?” to make sure your players are on board.
One side might surrender when almost all its members are defeated or if spells or skills thoroughly demoralize them. Once there's a surrender, come out of initiative order and enter a short negotiation. These conversations are really about whether the winners will show mercy to the losers or just kill or otherwise get rid of them. The surrendering side usually doesn't have much leverage in these cases, so avoid long back-and-forth discussions.
You can decide a fight is over if there's no challenge left and the player characters are just cleaning up the last few weak enemies. However, avoid doing this if any of the players still have inventive and interesting things they want to try or spells they're concentrating on—ending an encounter early is a tool to avoid boredom, not to deny someone their fun. You can end a fight early in several ways: the foes can surrender, an adversary can die before its Hit Points run out, or you can simply say the battle is over and that the PCs easily dispatch their remaining foes. In this last case, you might ask, “Is everyone okay if we call the fight?” to make sure your players are on board.
One side might surrender when almost all its members are defeated or if spells or skills thoroughly demoralize them. Once there's a surrender, come out of initiative order and enter a short negotiation. These conversations are really about whether the winners will show mercy to the losers or just kill or otherwise get rid of them. The surrendering side usually doesn't have much leverage in these cases, so avoid long back-and-forth discussions.
Fleeing Enemies
Source GM Core pg. 33
Fleeing enemies can sometimes cause issues at the game table, as players often want to pursue them, thinking they might return as a threat later. This can easily bog down the game and extend an encounter that has already reached its conclusion, so avoid playing this out move by move. If every adversary is fleeing, forgo initiative order and give each PC the option to pursue any one fleeing foe. Each PC can declare one action, spell, or other ability to use to try to keep up. Then, compare the PC's Speed to that of the target, assess how much the pursuer's chosen spell or ability would help, and factor in any abilities the quarry has that would aid escape. If you determine that the pursuer catches up, go back into combat with the original initiative order. If not, the quarry escapes for now.
Total Party Kills
Source GM Core pg. 33
Perhaps the most feared of any outcome of a gaming session, a total party kill (TPK) can spell the end of an adventure or campaign. In a TPK, every member of the party dies. Think in advance about how comfortable you are with TPKs and discuss them with the other players. This can provide valuable insights into not only how you should handle one, but also the implied level of lethality the players expect.
TPKs are rarely unavoidable. Usually it becomes evident at some point during the session—whether to everyone or only to you—that disaster looms. What the players do with this insight is up to them, but you have more control and can take steps to avoid the TPK. For example, perhaps the PCs' foe gets distracted by something, an ally arrives to help the heroes, or the villain captures them instead of slaying them outright. The simplest path is to just allow a clear escape route the PCs can take—perhaps with a few characters still falling along the way. It isn't entirely your responsibility to defuse the TPK, but offering such opportunities gives players more say in their characters' fates.
Should a TPK occur anyway, the kind of game you're running should influence your approach to the situation. For example, in a relatively story-light campaign centered around dungeon crawling, a TPK is less of a problem—the players simply form a new adventuring party and take up where the dead ones left off. If you're running a story-intensive game in which each PC has a personal stake in defeating the villain, saving the city, or the like, a TPK could require you to rework multiple plot threads. Here, you might use the story you have in place; for example, a player's new character might be the sibling of their previous, slain character, thus creating some continuity between the two characters and ensuring that the new character still has a stake in defeating the villain.
Note that the game should continue only if the players want it to. The premature end of an adventure or campaign isn't always a bad thing. If the group is interested in moving on, there's nothing wrong with ending the campaign and starting something different.
TPKs are rarely unavoidable. Usually it becomes evident at some point during the session—whether to everyone or only to you—that disaster looms. What the players do with this insight is up to them, but you have more control and can take steps to avoid the TPK. For example, perhaps the PCs' foe gets distracted by something, an ally arrives to help the heroes, or the villain captures them instead of slaying them outright. The simplest path is to just allow a clear escape route the PCs can take—perhaps with a few characters still falling along the way. It isn't entirely your responsibility to defuse the TPK, but offering such opportunities gives players more say in their characters' fates.
Should a TPK occur anyway, the kind of game you're running should influence your approach to the situation. For example, in a relatively story-light campaign centered around dungeon crawling, a TPK is less of a problem—the players simply form a new adventuring party and take up where the dead ones left off. If you're running a story-intensive game in which each PC has a personal stake in defeating the villain, saving the city, or the like, a TPK could require you to rework multiple plot threads. Here, you might use the story you have in place; for example, a player's new character might be the sibling of their previous, slain character, thus creating some continuity between the two characters and ensuring that the new character still has a stake in defeating the villain.
Note that the game should continue only if the players want it to. The premature end of an adventure or campaign isn't always a bad thing. If the group is interested in moving on, there's nothing wrong with ending the campaign and starting something different.