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 (e.g.: Cast when Damage Taken - Enduring Cry - Immortal Call will cast Enduring Cry first, allowing Immortal Call to consume the charges immediately. In the other order, Immortal Call with consume existing charges, then new charges will be produced by Enduring Cry). 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 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.
Cooldown: Cast when Damage Taken has a cooldown of 250ms, or the linked skill's cooldown, whichever is longer. Each linked spell has its own cooldown and internal damage counter. The damage counter will not increase while the spell is cooling down. This can cause skills intended to be simultaneous to get out of sync (e.g. Immortal Call will keep counting damage while Enduring Cry is on cooldown, so they will end up going off at different times).
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.
Damage Counter Reset: The counter of damage taken will reset to 0 whenever you enter a new area. Damage taken is not remembered when returning to the same instance of an area.
Gem level progression
|Level|| x% less
| Maximum Level of
This skill can be gained as a reward for finishing quests:
- A Fixture of Fate in Act 3 (Merciless), by all classes.
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.