Unique Attack Modifier

Orb effects in Dota 2 refer to attack modifiers that alter your heroes basic attack to provide an additional effect. An example of this is Helm of the Dominator, which gives your hero lifesteal. For balance and legacy reasons, orb effects, with very rare exceptions, do not stack. Having more than one at any time is generally considered useless. Certain hero abilities, such as Broodmother's Incapacitating Bite, also count as orb effects. Not all attack modifiers count as orbs.

When two orb effects are acquired by one hero, one will take priority. A hero skill will always take priority over items. For items, the first acquired will take priority.

All items in the Artifacts shop, with the notable exception of Yasha, grant orb effects.

Note that in Dota 2, unlike DotA, Mjollnir and Maelstrom, will override other orb effects whenever they proc, meaning they can be stacked.

Items that grant Orb Effects

 * [[Image:Helm_of_the_Dominator.png|Helm of the Dominator|40px|link=Helm of the Dominator]] Helm of the Dominator
 * [[Image:Mask_of_Madness.png‎|Mask of Madness|40px|link=Mask of Madness]] Mask of Madness
 * [[Image:Sange.png‎|Sange|40px|link=Sange]] Sange
 * [[Image:Maelstrom.png‎|Maelstrom|40px|link=Maelstrom]] Maelstrom
 * [[Image:Diffusal_Blade.png‎|Diffusal Blade|40px|link=Diffusal Blade]] Diffusal Blade
 * [[Image:Desolator.png|Desolator|40px|link=Desolator]] Desolator
 * [[Image:Sange_and_Yasha.png‎|Sange and Yasha|40px|link=Sange and Yasha]] Sange and Yasha
 * [[Image:Mjollnir.png‎|Mjollnir|40px|link=Mjollnir]] Mjollnir
 * [[Image:Skadi.png‎|Eye of Skadi|40px|link=Eye of Skadi]] Eye of Skadi (Melee only. Ranged is Buff Placer only)
 * [[Image:Satanic.png‎|Satanic|40px|link=Satanic]] Satanic
 * [[Image:Orb_of_Venom.png|Orb of Venom|40px|link=Orb_of_Venom]] Orb of Venom

List of hero skills that grant Orb Effects

 * [[Image:Mana_Break_icon.png|Mana Break|40px|link=Anti-Mage#Mana_Break]] Anti Mage's Mana Break
 * [[Image:Frost_Arrows_icon.png|Frost Arros|40px|link=Drow_Ranger#Frost_Arrows]] Drow Ranger's Frost Arrows
 * [[Image:Impetus_icon.png|Impetus|40px|link=Enchantress#Impetus]] Enchantress's Impetus
 * [[Image:Caustic_Finale_icon.png|Caustic Finale|40px|link=Sand_King#Caustic_Finale]] Sand King's Caustic Finale
 * [[Image:Incapacitating_Bite_icon.png|Incapacitating Bite|40px|link=Broodmother#Incapacitating_Bite]] Broodmother's Incapacitating Bite
 * [[Image:Poison_Attack_icon.png|Poison Attack|40px|link=Viper#Poison_Attack]] Viper's Poison Attack
 * [[Image:Geminate_Attack_icon.png|Geminate Attack|40px|link=Weaver#Geminate_Attack]] Weaver's Geminate Attack

Buff Placers
Many orb effects also count as Buff Placers. Buff Placers follow the same rules as Orb Effects, but count separately. Buff placers usually apply a "buff" (actually a debuff) to the target, and can be carried by an orb effect. For example, Desolator grants the Corruption Orb Effect attack modifier, which applies the Corruption (-6 Armor) debuff to the target.

Buff placers that are not Orb Effects will stack with Orb Effects, but not with each other. For example, Lifesteal from Helm of the Dominator will stack with Orb of Venom, which is a Buff Placer only, but not with Desolator or Maelstrom, which both contain Orb Effects.

The following is a list of Buff Placers that are not Orb Effects:


 * [[Image:Poison_Sting_icon.png|Poison Sting|40px|link=Venomancer#Poison_Sting]] Venomancer's Poison Sting
 * [[Image:Skadi.png‎|Eye of Skadi|40px|link=Eye of Skadi]] Eye of Skadi (only on ranged heroes)

Critical Strike and Bash
Critical Strike also counts as a Buff Placer for ranged heroes, on the attack in which it procs. Crystalys and Daedalus both grant Critical Strike. Monkey King Bar's True Strike ability also counts as a Critical Strike, but will not interfere with other Critical Strikes.

Bash likewise counts as a Buff Placer for ranged heroes on attacks in which it procs. Bash may be gained from Skull Basher.

Stacking
In Dota 2 Orb Effects generally do not stack, with one orb effect always taking priority. There are several exceptions to this, however. Mjollnir and Maelstrom currently will work with other orbs, overriding them whenever the chain lightning occurs. Lifesteal will work with both ranged and melee Eye of Skadi.

Otherwise, all hero skills will override any orb effects obtained from items. For other orb effects, the first acquired will take priority.

Note that activatable Orb Effect skills only count as orb effects when cast, either from autocast or manually, and so can theoretically be used part of the time, with another orb effect active the rest. In practice this is rarely useful.