!.C.D 💣 Damage - JulTob/DnD GitHub Wiki
Damage
Injury and the risk of death are constant companions of those who explore fantasy gaming worlds.
The thrust of a sword, a well-placed arrow, or a blast of flame from a fireball spell all have the potential to damage, or even kill, the hardiest of creatures.
Hit Points
Hit points represent a combination of physical and mental durability, the will to live, and luck.
Creatures with more hit points are more difficult to kill.
Those with fewer hit points are more fragile.
A creature's current hit points (usually just called hit points) can be any number from the creature's hit point maximum down to 0. This number changes frequently as a creature takes damage or receives healing.
Whenever a creature takes damage, that damage is subtracted from its hit points.
The loss of hit points has no effect on a creature's capabilities until the creature drops to 0 hit points.
Damage Rolls
Each weapon, spell, and harmful monster ability specifies the damage it deals.
You roll the damage die or dice, add any modifiers, and apply the damage to your target.
Magic weapons, special abilities, and other factors can grant a bonus to damage.
With a penalty, it is possible to deal 0 damage, but never negative damage.
When attacking with a weapon, you add your ability modifier--the same modifier used for the attack roll--to the damage.
A spell tells you which dice to roll for damage and whether to add any modifiers.
If a spell or other effect deals damage to more than one target at the same time, roll the damage once for all of them.
For example, when a wizard casts fireball or a cleric casts flame strike, the spell's damage is rolled once for all creatures caught in the blast.
Critical Hits
When you score a critical hit, you get to roll extra dice for the attack's damage against the target. Roll all of the attack's damage dice twice and add them together.
Then add any relevant modifiers as normal.
To speed up play, you can roll all the damage dice at once.
For example, if you score a critical hit with a dagger, roll 2d4 for the damage, rather than 1d4, and then add your relevant ability modifier. If the attack involves other damage dice, such as from the rogue's Sneak Attack feature, you roll those dice twice as well.
Damage Types
Different attacks, damaging spells, and other harmful effects deal different types of damage.
Damage types have no rules of their own, but other rules, such as damage resistance, rely on the types.
The damage types follow, with examples to help a DM assign a damage type to a new effect.
Acid. The corrosive spray of an adult black dragon's breath and the dissolving enzymes secreted by a black pudding deal acid damage.
Bludgeoning. Blunt force attacks--hammers, falling, constriction, and the like--deal bludgeoning damage.
Cold. The infernal chill radiating from an ice devil's spear and the frigid blast of a young white dragon's breath deal cold damage.
Fire. Ancient red dragons breathe fire, and many spells conjure flames to deal fire damage.
Force. Force is pure magical energy focused into a damaging form. Most effects that deal force damage are spells, including magic missile and spiritual weapon.
Lightning. A lightning bolt spell and a blue dragon wyrmling's breath deal lightning damage.
Necrotic. Necrotic damage, dealt by certain undead and a spell such as chill touch, withers matter and even the soul.
Piercing. Puncturing and impaling attacks, including spears and monsters' bites, deal piercing damage.
Poison. Venomous stings and the toxic gas of an adult green dragon's breath deal poison damage.
Psychic. Mental abilities such as a psionic blast deal psychic damage.
Radiant. Radiant damage, dealt by a cleric's flame strike spell or an angel's smiting weapon, sears the flesh like fire and overloads the spirit with power.
Slashing. Swords, axes, and monsters' claws deal slashing damage.
Thunder. A concussive burst of sound, such as the effect of the thunderwave spell, deals thunder damage.
Damage Resistance and Vulnerability

Some creatures and objects are exceedingly difficult or unusually easy to hurt with certain types of damage.
If a creature or an object has resistance to a damage type, damage of that type is halved against it.
If a creature or an object has vulnerability to a damage type, damage of that type is doubled against it.
Resistance and then vulnerability are 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 or vulnerability 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 against the creature, not reduced by three-quarters.