Combat

Actions in Combat

On your turn, you can move a distance up to your speed, take one action and a bonus action. You can also interact with one object or feature of the environment for free, during either your move or your action.

The most common actions during combat is to attack. Other examples of actions you can take during combat are: Dash. You gain extra movement for the current turn equal your speed.

Disengage. Your movement doesn’t provoke opportunity attacks for the rest of the turn.

Dodge. Until the start of your next turn, any attack roll made against you has disadvantage if you can see the attacker, and you make Dexterity saving throws with advantage. You lose this benefit if you are incapacitated or if your speed drops to 0.

Help. A creature you aid gains advantage on the next ability check it makes to perform the task you are helping with, provided that it makes the check before the start of your next turn. Alternatively, you can aid in attacking a creature within 5 feet of you. The first attack roll against it before your next turn is made with advantage.

Ready. Prepare in order to use your action as a reaction, in response to a trigger that you decide. First, decide what perceivable circumstance will trigger your reaction. Then, choose the action you will take in response to that trigger. When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger.

Ready a Spell. When you ready a spell, you cast it as normal but hold its energy, which you release with your reaction when the trigger occurs. To be readied, a spell must have a casting time of 1 action, and holding onto the spell’s magic requires concentration. If your concentration is broken, the spell dissipates without taking effect.

Use an Object. Useful when you want to interact with more than one object on your turn.

Cover

A target with half cover has a +2 bonus to AC and Dexterity saving throws. A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend.

A target with three-quarters cover has a +5 bonus to AC and Dexterity saving throws. The obstacle might be an overturned table, an arrow slit, or a thick tree trunk.

A target with total cover can’t be targeted directly by an attack or a spell.

Dropping to 0 hp

When damage reduces you to 0 hit points and there is damage remaining, you die if the remaining damage equals or exceeds your hit point maximum.

If the remaining damage exceeds your Constitution score, your first Death save is made with disadvantage, and if it is below or equal to your Constitution bonus or 0, it is made with advantage.

You can use your action to administer first aid to an unconscious creature and attempt to stabilize it, which requires a successful DC 10 Wisdom (Medicine) check. A stable creature that isn’t healed regains 1 hit point after 1d4 hours. However, it does benefit from spending a use from a Healer’s kit if it has remaining hit dice.

After you regain hp to bring you above 0 hp it takes a few rounds to adjust; you get 6 levels of combat exhaustion. This is added to you normal exhaustion, but reaching level 6 (or higher) does not kill you, instead you count as stunned. You loose 1 level of combat exhaustion at the start of each of your rounds.

Initiative

Reaction speed is determined first-and-foremost by your thoughts — the faster you can think, the faster your brain can tell your body to act. When rolling for initiative, do not add your Dexterity modifier — instead, add your Intelligence modifier. Break ties first with Dexterity, then Wisdom.

Jumping

Long Jump
A long jump covers a number of feet up to your Strength score if you move at least 10 feet on foot immediately before the jump. When making a standing long jump, you can leap only half that distance. When you land in difficult terrain, you must succeed on a DC 10 Dexterity (Acrobatics) check to land on your feet. Otherwise, you land prone.

High Jump
When making a high jump, you leap a number of feet equal to 3 + your Strength modifier if you move at least 10 feet on foot immediately before the jump. When you make a standing high jump, you jump only half that distance.

You can extend your arms half your height above yourself during the jump. Thus, you can reach above you a distance equal to the height of the jump plus 1 1/2 times your height.

Mounted Combat

Mounting or dismounting costs an amount of movement equal to half your speed. If an effect moves your mount against its will, you must succeed on a DC 10 Dexterity saving throw or fall off, landing prone. If you’re knocked prone while mounted, you must make the same saving throw. If your mount is knocked prone, you can use your reaction to dismount it as it falls and land on your feet. Otherwise, you are dismounted and fall prone.

While mounted, you can either control the mount or allow it to act independently. You can control a mount only if it has been trained to accept a rider, in which case its initiative changes to match yours. It moves as you direct it, and it has only three action options: Dash, Disengage and Dodge.

An independent mount retains its place in the initiative order. Bearing a rider puts no restrictions on the actions the mount can take, and it moves and acts as it wishes. It might flee from combat, rush to attack and devour a badly injured foe, or otherwise act against your wishes. In either case, if the mount provokes an opportunity attack while you’re on it, the attacker can target you or the mount.

Movement

Every character and monster has a speed, which is the distance in feet that the character or monster can move in 1 round. This number assumes short bursts of energetic movement in the midst of a lifethreatening situation.

Your movement can include jumping, flying and climbing, and you simply deduct the distance of each part of your move from your speed until it is used up or you are done moving.

Every foot of movement in difficult terrain costs 1 extra foot. The space of another creature, whether hostile or not, also counts as difficult terrain.

You can drop prone without using any of your speed. Standing up costs an amount of movement equal to half your speed. You can’t stand up if you don’t have enough movement left or if your speed is 0. To move while prone, you must crawl, which costs 1 extra foot. Crawling 1 foot in difficult terrain, therefore, costs 3 feet of movement.

Resistances

Resistance is applied after all other modifiers to damage. For example, a creature has resistance to bludgeoning damage and is hit by an attack that deals 25 bludgeoning damage. The creature is also within a magical aura that reduces all damage by 5. The 25 damage is first reduced by 5 and then halved, so the creature takes 10 damage.

Multiple instances of resistance that affect the same damage type count as only one instance. For example, if a creature has resistance to fire damage as well as resistance to all nonmagical damage, the damage of a nonmagical fire is reduced by half, not by three-quarters damage.

Sneaking and Stabbing

Sneaking up to a guard and and knocking him out is fully possible. If you are undetected, make an attack roll with advantage. If you hit, and the target is Humanoid, it makes a Constitution save to avoid being knocked out. The difficulty of the save depends on whether the target has protection, like a helmet.

Rogues are a little better at this, forcing the target to make their save with disadvantage.

Surprise

Any character or monster that doesn’t notice a threat is surprised at the start of the encounter. If you’re surprised, you can’t move or take an action on your first turn of the combat. Additionally you can’t take a reaction until you have acted.

Underwater Combat

Melee weapon attacks have disadvantage on the attack roll unless the weapon deals piercing damage. Ranged weapon attacks automatically miss targets beyond the weapon’s normal range. Even against a target within normal range, the attack roll has disadvantage unless the weapon is a crossbow or a weapon that is thrown like a javelin (including a spear, trident or dart). Creatures and objects that are fully immersed in water have resistance to fire damage.