Item passive stacking

Item passive stacking describes the interactions between multiple items that have similar effects. The stacking of items fall into different categories, and the stacking of each category is handled differently.

Independent stacking

• Bonus damage
• Bonus attributes (strength/agility/intelligence)
• Bonus mana/health (static amount)
• Bonus health regeneration/mana regeneration
• Bonus attack speed
• Bonus armor
• Cleave %
• Damage from Monkey King Bar

Items that stack independently do not interfere with each other in any way. If a Hero has two Monkey King Bars, each attack will trigger two separate chances to mini-bash, giving a 57.75% chance of one mini-bash and a 12.25% chance of two mini-bashes.

Chance stacking

• Damage block
• Critical strike

Items that chance stack are each given an opportunity to apply their effects, in order of highest effect to lowest.

• If a Hero buys both a Crystalys and a Daedalus, on every hit the Hero has a 25% chance of receiving the Daedalus critical damage, a 20% chance of receiving the Crystalys critical damage, and a ~5% chance of receiving both. Unlike the independent stacking case, if both effects are received the Daedalus overrides the Crystalys because it has a higher critical chance multiplier.
• You have a Vanguard and then get a Stout Shield (on a melee hero): Since the Vanguard has a better block effect, you have a 70% chance to block 40 damage, an 18% chance to take 20 less damage and 12% chance to take normal damage.

Items that do not stack

Bloodstone

Multiple Bloodstones do not reduce respawn time further. Only the Bloodstone in the highest priority slot works.

• Priority slots are as follows:

1 2 3

4 5 6

Skull Basher

The strength and damage components of multiple Skull Bashers will independently stack, but the bash chance will not.

Magic resistance

Magic resistance from Cloak, Hood of Defiance, or Pipe of Insight do not stack. Only the latest acquired works.

Evasion

There are two instances of a Hero missing an attack, from a status effect exhibited by the attacking unit such as being drenched in Brewmaster's Drunken Haze, or from an ability exhibited by the attacked unit such as Windrunner's Windrun. The two are considered separate instances, where the former triggers upon attack while the latter triggers upon receiving damage. In a sense, if a Hero were to miss his attack, the dice for evasion would not roll. If the Hero does successfully proc where his attack goes through the debuff, then the dice for evasion roll. Only the highest value works per instance.

However, Faceless Void's Backtrack can stack with evasion as it is not a similar trigger.

Auras

Auras do not stack with themselves, since they place a buff on the unit. Only the aura with the highest value will work. Note that some items share a specific aura (Ring of Basilius and Vladmir's Offering). In this case, only Vladimir's Offering's mana regeneration aura and armor aura will work.

Unique Attack Modifiers

An attack can only have one Unique Attack Modifier. Priority and exceptions are explained here.