Damage block

Damage Block is a passive ability that gives the wielding unit a chance to block some physical damage from an attack.

Mechanics
Damage Block has a chance to proc from attack damage, but not physical damage from abilities (except for, , and physical damage reflected by or ). Only the attack damage from wards is not reduced by Damage Block. Unlike armor, Damage Block only reduces a set amount of damage, making it less useful over time.

Damage Block occurs as first step of incoming damage manipulation. See Final Attack Damage for the complete calculation.

All items that use Damage Block mechanics use pseudo-random distribution.

Most Damage Block items block different amounts depending on whether the user is melee or ranged. also has a reduced chance to proc from non-hero damage.

Stacking
Only one instance of Damage Block can proc at a time. When multiple sources of Damage Block are present, the source with the highest blocked damage is checked first, and only if it does not proc any others roll. In other words, when two sources of Damage Block have the same chance to proc, the one that blocks more damage takes priority. While the amount of damage blocked from multiple Damage Block sources does not stack, the proc chance stacks multiplicatively. For example, when having two s, the chance of blocking damage becomes 50% + 50% * 0.5, effectively having a 75% chance to block 16/8 damage.