Critical Strike

Critical Strike is a passive ability that gives the chance to deal a bonus percentage damage on a succesful attack of the weilding unit.

Mechanics
Critical Strike is defined by two values: the Critical Chance and the Critical Damage multiplicator. It is physical damage and 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). Critical Strike does not work against Buildings and is subject to Pseudo-random distribution. Because Critical Strike multiplies the attack damage of a unit, it is a scaling ability (unlike the damage of Monkey King Bar's Mini-Bash ability).

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.
 * Illusions: Illusions can use the Critical Strike ability.

Sources of Critical Strike