Trigger

Trigger effects cause a skill to activate instantly when a specified condition is met, without requiring an animation. They have slightly different behaviour depending on whether they are an active gem or linked to a trigger gem or item. Modifiers on items and support gems that trigger a skill have a percentage-based Cost and Reservation Multiplier. This essentially means that triggered skills still require sufficient resources to activate, unless stated otherwise.

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 does not interrupt the player's 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. When a 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, Cast On Critical Strike Support 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 Mjölner that has Arc, Spark, and Discharge 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 unique items have an exception to this rule:

• Null's Inclination casts all socketed minion skills at the same time when triggered, but is limited by charge count, which replenish over time.
• Kitava's Thirst 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, Detonate Mines 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 modified by cooldown affixes such as those found on boots and belts but not by Second Wind Support. 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 Cold Snap.

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.

The linked sockets also follow a specific order, as follows:

    １    ⇒    ２
               ⇓
    ４    ⇐    ３
⇓        
    ５    ⇒    ６

If multiple trigger gems are socketed in several equipped items the order will be:

• Main hand ⇒ Amulet ⇒ Helmet ⇒ Off hand ⇒ Body armour ⇒ Gloves ⇒ Boots

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.