Cast when Damage Taken
This Gem can only Support Skill Gems requiring Level x or lower
x% less Damage
You cannot Cast Supported Spells directly
100% chance to Cast Supported Spells when you take a total of x Damage
Skill Functions and Interactions
Trigger Gem: Like all trigger gems, Cast when Damage Taken only "casts" spells. Attack gems such as Double Strike are not considered spells. Multiple spells can be linked to a single trigger gem but if two or more spells are of the same type (e.g.: Cast when Damage Taken - Fireball - Fireball) they will never trigger simultaneously, even if they are not on the same link. The order in which they are linked determines the order in which they cast. The top end of the linked sockets (for four-links, the top left socket) is the first in the order, followed by each socket down the line, following links.
Damage Counter and Cooldown: Each linked skill has an internal damage counter that tracks the total accumulated damage taken from hits, but not from damage over time or the Blood Magic passive (e.g. you cannot use Righteous Fire to trigger Cast when Damage Taken). All damage counters will be reset to 0 upon entering a new area. When a linked skill is cast, its damage counter will go on cooldown for 250 ms and will not track damage during that time. Furthermore, Cast when Damage Taken has its own cooldown of 250 ms, and a linked skill can only be cast when both its own damage counter and Cast when Damage Taken are not on cooldown. This can cause skills intended to be simultaneous to get out of sync.
Damage effectiveness: The damage effectiveness increases with level, but so does the damage taken per cast; overall, the amount of damage that needs to be taken per damage effectiveness goes up at higher gem levels. The optimum is a level 2 gem, which requires 1442 damage taken per 100% damage effectiveness. In comparison, a level 20 gem requires 3057 damage taken per 100% damage effectiveness.
Targeting: Targeted spells will cast towards the enemy that caused the last damage. Reflected damage is considered to come from the enemy originally damaged.
Maximum Level of Supported Skills: Cast when Damage Taken cannot support skills of higher level than specified. Note that this restriction only applies to active skills; any level of supports may be used.
Gem level progression
|Level|| x% less
| Maximum Level of
Quest rewardThis skill is given as quest reward for the following quests:
|Sharp and Cruel|
Vendor rewardThis skill can be bought at the listed npc vendors after completing the following quests:
|The Eternal Nightmare|
Petarus and Vanja
Due to the large amount of damage taken needed per damage effectiveness and the rapid scaling of damage taken required per level, it is advisable to use spells for purposes other than damage that do not depend heavily on the active skill level. Possible choices include:
- to block enemies.
- to create ground ice.
- Passive corpse disposal/minion buffing via , , or .
- to escape melee range. (Could backfire.)
- Curses. This can be a reliable way of automatically casting curses, at the cost of lower curse level.
Some supports also potentially combine well, especially with a persistent rapid-firing skill such as:
- Passive IIR culling via , , and a skill that causes many hits.
Cats when Damage Taken
Cats when Damage Taken was a trigger gem available only on April 1st 2015. It was a bug caused by a typo in source code. Like Cast when Damage Taken, it caused a linked spell to activate when the player accumulated damage taken, but besides casting the spell, it also summoned black cats. Other properties were identical to the Cast when Damage Taken skill.
- Mark_GGG (9 October 2013). "Path of Exile Forum". Retrieved 2 July 2015.
- Chris (April 1, 2015). "Incident Report for April 1 Catastrophe". Retrieved April 1, 2015.