Critical Strike

Critical strike is a passive ability that gives the chance to deal a bonus percentage damage on a successful attack of the wielding unit.

Mechanics
Skeleton King performing a Critical Strike. The red number displays the resulting physical damage before reductions.]] Critical strike is defined by two values: the critical chance and the critical damage multiplier.

Critical damage is physical damage and is reduced by various types of armor. The red number shown by critical strike is displayed before reductions (this is why illusions don't show very low red numbers) excepted for Chaos Knight's illusions with his ultimate that do the full damages. Critical strike does not work against buildings. Because critical strike multiplies the attack damage of a unit, after damage modifiers, it is a scaling ability (unlike the damage of Monkey King Bar's mini-bash ability). All critical strikes are subject to pseudo-random distribution.

Interaction with other passive abilities

 * Critical strike: Multiple critical strike abilities do not independently stack, as they can not trigger on the same hit.
 * Lifesteal: Lifesteal is calculated after critical strikes, which means that it will increase the amount of life you steal.
 * Cleave: If critical strike is triggered, the damage dealt to all units will be multiplied.
 * Bash: Bashes and Critical Strikes can proc off of the same attack, and are never multiplied.
 * Illusions: Illusions can use the critical strike ability. (The red number above the unit is damage before the illusion reduction) Pseudo-Critical strike cannot be used by illusions.

Pseudo-Critical Strike
The following abilities involve a critical strike mechanic, although they are not triggered as a chance on attack.