Player Core Chapter 8: Playing The Game Encounter Mode

Special Battles

Mounted Combat

You can ride some creatures into combat. As noted in the Mount specialty basic action, your mount needs to be willing and at least one size larger than you. Your mount acts on your initiative. You must use the Command an Animal action to get your mount to spend its actions. If you don't, the animal wastes its actions. If you have the Ride general feat, you succeed automatically when you Command an Animal that's your mount.
For example, if you're mounted on an animal and you make three attacks, your mount would remain stationary since you didn't command it. If you instead spent your first action to Command an Animal and succeeded, you could get your mount to Stride. You could spend your next action to attack or to command the mount to attack, but not both.

Mounted Attacks

Source Player Core pg. 429

You and your mount fight as a unit. Consequently, you share a multiple attack penalty. For example, if you Strike and then Command an Animal to have your mount Strike, your mount's attack takes a –5 multiple attack penalty.
You occupy every square of your mount's space for the purpose of making attacks. If you were a Medium creature on a Large mount, you could attack a creature on one side of your mount, then attack on the opposite side. On a Medium or smaller mount, use the normal reach of an attack. On a Large or Huge mount, you can attack any square adjacent to the mount if you have 5- or 10-foot reach, or any square within 10 feet of the mount (including diagonally) if you have 15-foot reach. Use the adjusted reach for determining flanking and other rules that depend on reach.

Mounted Defenses

Source Player Core pg. 429

Attackers can target either you or your mount. An area effect affects both of you as long as you're both in the area. You're in an attacker's reach or range if any square of your mount is within reach or range. Because your mount is larger than you and you share its space, you have lesser cover against attacks targeting you when you're mounted if the mount would be in the way (as determined by the GM).
Because you can't move your body as freely while you're riding a mount, you take a –2 circumstance penalty to Reflex saves while mounted. Additionally, the only move action you can use is the Mount action to dismount.

Aerial Combat

Source Player Core pg. 429

Many monsters can fly, and PCs can use spells and items to gain the ability to fly. Flying creatures have to use the Fly action to move through the air. Performing an especially tricky maneuver might require using Acrobatics to Maneuver in Flight. Creatures might fall from the sky, using the falling rules. At the GM's discretion, some groundbased actions might not work in the air. For instance, a flying creature couldn't Leap.

In aerial and aquatic combat, you might need to track positioning in three dimensions. For flying creatures, you might use one of the following methods.

Find platforms to place flying creatures' miniatures on.
Set a die next to a creature with the number indicating how many squares up in the air it is.
Make a stack of dice or tokens, 1 per 5 feet of elevation.
Write the elevation next to the monster on the grid.

In underwater combat, choose a plane to be the baseline, typically the waterline, the sea floor, or a stationary object you can measure from.
As with ground-based movement, moving diagonally up or down in 3-D space requires counting every other diagonal as 10 feet. Measure flanking in all directions— creatures above and below an enemy can flank it just as effectively as they can from opposite sides.

Aquatic Combat

Source Player Core pg. 429

Use these rules for battles in water or underwater.

You're off-guard unless you have a swim Speed.
You gain resistance 5 to acid and fire.
You take a –2 circumstance penalty to your attack rolls for bludgeoning or slashing attacks that pass through water.
Ranged attacks made by an underwater creature or against an underwater target have their range increments halved.
You can't cast fire spells or use actions with the fire trait underwater. As normal for how traits work, any part of the effect that's unrelated to fire still works. For example, an attack with a flaming fangblade could still deal its physical damage, just not its fire damage.
At the GM's discretion, some ground-based actions might not work underwater or while floating.

Drowning and Suffocating

Source Player Core pg. 429

You can hold your breath for a number of rounds equal to 5 + your Constitution modifier. Reduce your remaining air by 1 round at the end of each of your turns, or by 2 if you attacked or cast any spells that turn. You also lose 1 round worth of air each time you are critically hit or critically fail a save against a damaging effect. If you speak (including Casting a Spell), you lose all remaining air.
When you run out of air, you fall unconscious and start suffocating. You can't recover from being unconscious and must attempt a DC 20 Fortitude save at the end of each of your turns. On a failure, you take 1d10 damage, and on a critical failure, you die. On each check after the first, the DC increases by 5 and the damage by 1d10; these increases are cumulative. Once your access to air is restored, you stop suffocating and are no longer unconscious (unless you're at 0 Hit Points).