Damage

Damage is the means of depleting an enemy unit's Health. All damage in the game is divided in to two main damage types: Physical and Spell damage. As a rule of thumb Basic Attacks deal Physical damage and Abilities and Talents deal Spell Damage. Like with Armor, when in-game tooltip mentions only "damage" it usually includes both Physical and Spell damage. Damage types work together with Armor types and damage modifiers to further enhance a hero's strengths and weaknesses. Most heroes are focused on one type of damage at the expense of others, while some heroes are resistant to certain forms of damage.

Physical Damage
Basic Attacks of most in-game units deal Physical damage. Floating damage text will display Physical Damage as orange numbers above the target's head. Physical damage taken is reduced by positive and increased by negative Armor and Physical Armor. Physical damage dealt can also be permanently or temporarily modified through Talents and Abilities, whether it be decreasing an attacker's damage (Shrink Ray) or increasing your own damage (Executioner). Heroes focused on basic attack damage are generally designed to deal high sustained damage.

Spell Damage
In contrast to Physical damage, the majority of Abilities and Talents of in-game units deal Spell damage. Floating damage text will display Spell Damage as purple numbers. Spell Damage dealt is modified by caster's Spell Power and all-damage modifiers. Spell damage taken is modified by Armor and Spell Armor. While all abilities deal Spell damage, some Abilities and Talents can temporarily make a unit's Basic Attacks deal Spell Damage. Heroes with a focus on spell damage are generally focused on dealing a higher amount of damage in a shorter period of time in the form of burst.

Non-heroic Summons' Basic Attacks deal Spell damage. This damage is modified by its owner's current Spell Power.

Health percent Damage
Health percent damage, is a special category of Spell damage that resembles other MOBAs' 'Pure' damage type. Abilities and Talents that deal damage based on a percentage of the target's maximum, current or missing Health do Percent damage. Health-based damage is dealt in Spell damage, but is flagged to ignore damage modifiers entirely.

Damage modifiers
Damage modifiers are effects that affect the damage dealt or received by the unit based on given percentage of the base value.