Trigger

Trigger effects cause a skill to activate instantly when a specified condition is met, without spending its mana cost or requiring an animation. They have slightly different behaviour depending on whether they are an active gem or linked to a trigger gem or item.

Mechanics
Trigger effects can come in different forms:
 * Active trigger skills will, when their condition is met, trigger an automatic skill to occur. This skill uses no mana and does not interrupt the players other actions. They do not require any supports to function, but any supports linked will apply to the skill. Active trigger skills can be supported by trigger support skills which require another skill as part of their triggering condition.
 * Support trigger skills must be supporting a skill, and when their condition is met, they trigger the skill without requiring an animation or mana. When an triggerable active skill is linked to a trigger effect, it cannot be used by the player manually. Some support trigger skills must also be supporting a second active skill as the basis for their trigger condition. For example, must be linked to both an attack gem and a spell gem to function.

Interactions
Multiple trigger supports: A single skill cannot have multiple triggers. Having more than one trigger condition will cause those skills to be disabled.

Multiple triggered skills: Only one supported skill will be cast per trigger. The spell that is triggered is determined based on the order in which it is socketed, and will cast supported spells in sequence, even across multiple attacks. For example, a that has, , and  socketed in that order will cast Arc on the first hit, Spark on the second, Discharge on the third, then back to Arc on the fourth, and so on. Some uniques have an exception to this rule:
 * casts all socketed minion skills at the same time when triggered.
 * will cast all socketed spells on trigger, but will only cast one of each unique spell.

Traps/Mines: Traps and mines cannot be triggered by any trigger effect, but will still be disabled when linked to an applicable triggers. However, skill gem can be linked to a trigger gem.

Totems: Totems cannot be summoned using triggers. Totems can not trigger any further effects themselves as well.

Vaal skills: Vaal skills cannot be triggered, even if the player has the required amount of souls.

Cooldowns: The trigger cooldown duration for a skill from triggering the skill varies for each trigger condition but they can be decreased by cooldown affixes such as those found on boots and belts but not by. Skills in the same trigger setup can be triggered while other skills in the same setup are on cooldown. Trigger effects cannot bypass inherent cooldowns such as the 3 second cooldown of.

Targeting: Directional spells will cast towards the triggering enemy. If the enemy was killed by the triggering attack, it will cast towards the cursor or in a random direction.

Using: Triggering a skill does not count as you using a skill. Therefore, effects that specify "when you Use a Skill", "when you Cast a Spell", "when you Attack", etc. will not work with triggers.

Order
This second order still follows the first rule of order. It will trigger Main Hand 1 to Amulet (1) to Helm 1 etc. before triggering the second socket on each piece of gear.

Due to this you should put gems, that have priority in the first or second socket and gems that rely on the priority gems to be triggered in socket numbers higher than those.

Unique items
The following unique items have a trigger effect:

Version history

 * For, , and , only one skill can be triggered per trigger event. The damage of Cast on Critical Strike and Cast on Melee Kill has been increased, as described in "Active Skill Gem Balance" below.
 * The spell that is triggered is determined based on the order in which it is socketed, and will cast supported spells in sequence, even across multiple attacks. These items and skills also have cooldowns which limit how often a skill is cast.
 * These cooldowns apply per-triggered-skill, rather than applying to the trigger gem itself.
 * All unique items that trigger skills, now and going forward, follow the rule that if a skill is triggered, it can only be used by that trigger and cannot be directly cast by the player as well.
 * Previously, only the trigger support gems limited the use of the triggered skills this way, while skills triggered by unique item properties could be self-cast.
 * will not be affected by the Cast on Crit changes and will still trigger all minion spells on kill.


 * Added Reckoning, Riposte, and Vengeance (Counter-attacks) to the game.


 * We have restricted skills to only work with a single trigger gem at a time. Skills supported by multiple triggers will be disabled and won't work with any of them.


 * We've added Trigger Gems, a new type of Support Gem that causes linked skills to be cast automatically on certain conditions. This patch includes six of these, with more coming in subsequent updates.
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