Cast when Damage Taken Support

Cast when Damage Taken is a support gem. It causes a linked spell to trigger when the player takes a certain amount of 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, and will all be triggered if so. Multiple copies of Cast when Damage Taken will also function independently.

Damage counter and cooldown: Each linked spell gains an internal damage counter that tracks the total accumulated damage taken from hits, though not from damage over time or the Blood Magic passive (e.g. you cannot use to trigger Cast when Damage Taken). All damage counters will be reset to 0 upon entering a new area. When a linked spell is cast, it is put on cooldown for 250 ms and will not track damage during that time.

Multiple copies of the same gem share cooldowns, meaning that if two copies of the same spell are triggered within 250 ms of each other, the first will trigger and the second will fail to do so as it is on cooldown. This mostly prevents using multiple copies of the same spell with Cast when Damage Taken, though the use of Cast when Damage Taken gems of different levels can avoid cooldown overlap in some circumstances due to the differing amounts of damage required to trigger the spells.

The Cast when Damage Taken gem itself does not have its own counter or cooldown.

Damage taken: The damage taken is applied after mitigations so armour, resistances, and less damage taken of "X" will reduce the number of procs. The damage does not have to apply to life though so damage to ES, mana (through Mind Over Matter), ward, Guard Skills, or other shields like Aegis all count. Shields from other sources such as Frost Shield will not count nor does Immortal Call since it reads as less damage taken.

Maximum level of supported skills: Cast when Damage Taken cannot support skills with a higher player level requirement than that of Cast when Damage Taken itself. Note that this restriction only applies to active skills; any level of other support gems may be used.

Trigger order: Trigger gems and their linked skills are cast in a certain order that depends both on which item it is equipped on and which socket the skills are in. If there are trigger gems in each equipped item, the order of operation will be:

Main hand ⇒ Amulet ⇒ Helm ⇒ Off hand ⇒ Body armour ⇒ Gloves ⇒ Boots

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

1	⇒	2
		⇓
4	⇐	3
⇓
5	⇒	6

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.

This does not, however, take into account the increase in damage from being able to use a higher level gem; for instance, a level 4 gem deals an average of 91.5 damage, while a level 20 gem deals an average of 475. On a strict damage-in-per-damage-out basis, Cast when Damage Taken roughly triples in power between level 1 and level 20, depending on the skill used. Any flat added damage will affect this ratio—the more damage added, the less effective it is to level up the Cast when Damage Taken gem.

Targeting: Targeted spells will cast towards the enemy that caused the last damage. Reflected damage is considered to come from the enemy originally damaged. If the damage was self-caused, it will target a random enemy (if there are no enemies, it will be cast at the player, if it is a projectile, it will be fired in a random direction).

Totems: Cast when Damage Taken can't be used with totems.

Gem level progression

Level				Damage Threshold	less/more Damage	Maximum Level of Supported Skill Gems	Exp.	Total Exp.
1	38	40	27	528	70% less	38	0	0
2	40	41	29	583	66% less	40	388734	388734
3	42	43	30	661	62% less	42	477437	866171
4	44	45	31	725	58% less	44	583786	1449957
5	46	47	33	812	54% less	46	710359	2160316
6	48	49	34	897	50% less	48	1355511	3515827
7	50	51	35	1003	46% less	50	1138877	4654704
8	52	53	37	1107	42% less	52	1368233	6022937
9	54	55	38	1221	38% less	54	1638338	7661275
10	56	57	39	1354	34% less	56	1956648	9617923
11	58	58	41	1485	30% less	58	3655184	13273107
12	60	60	42	1635	26% less	60	3017327	16290434
13	62	62	43	1804	22% less	62	3576232	19866666
14	64	64	44	1980	18% less	64	4231667	24098333
15	65	65	45	2184	14% less	65	2395078	26493411
16	66	66	46	2394	10% less	66	8421063	34914474
17	67	67	46	2621	6% less	67	16159983	51074457
18	68	68	47	2874	2% less	68	41170367	92244824
19	69	69	48	3142	2% more	69	86794448	179039272
20	70	70	48	3272	6% more	70	157405063	336444335
21	72	72	50	3580	10% more	72	N/A	N/A
22	74	N/A	N/A	3950	14% more	74	N/A	N/A
23	76	N/A	N/A	4350	18% more	76	N/A	N/A
24	78	N/A	N/A	4780	22% more	78	N/A	N/A
25	80	N/A	N/A	5240	26% more	80	N/A	N/A
26	82	N/A	N/A	5730	30% more	82	N/A	N/A
27	84	N/A	N/A	6250	34% more	84	N/A	N/A
28	86	N/A	N/A	6800	38% more	86	N/A	N/A
29	88	N/A	N/A	7380	42% more	88	N/A	N/A
30	90	N/A	N/A	7990	46% more	90	N/A	N/A
31	91	N/A	N/A	8310	48% more	91	N/A	N/A
32	92	N/A	N/A	8630	50% more	92	N/A	N/A
33	93	N/A	N/A	8965	52% more	93	N/A	N/A
34	94	N/A	N/A	9300	54% more	94	N/A	N/A
35	95	N/A	N/A	9650	56% more	95	N/A	N/A
36	96	N/A	N/A	10000	58% more	96	N/A	N/A
37	97	N/A	N/A	10365	60% more	97	N/A	N/A
38	98	N/A	N/A	10730	62% more	98	N/A	N/A
39	99	N/A	N/A	11110	64% more	99	N/A	N/A
40	100	N/A	N/A	11490	66% more	100	N/A	N/A

Related unique items

The following unique items are related to Cast when Damage Taken Support:

Strategy

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:

Offensive:

• to proc Elemental Overload for slow hitting/no hitting builds (e.g. DOT).
  • Can be linked to for even more consistent crit.
• Rapid-fire duration skills such as or for applying Elemental Overload and Elemental Equilibrium.
• for applying Exposure
• for applying Cold Exposure and reducing enemies' Life/Energy Shield regen
• for Frenzy Charge generation
• Offensive curses such as , , , , , , etc.
• Offensive golems such as , ,

Defensive:

• Guard skills such as , , , ,
  • Only one guard skill should be used in all CWDT setups, as they share their cooldown
  • can be used to increase the duration
• for increased block chance.
• for Elusive and Phasing.
• for increased movement speed, reduced visibility and Phasing
  • Useful for builds that often run past packs such as minion or DOT builds
  • Make sure Phase Run is the last skill to be triggered in all CWDT setups
• to block enemies.
• to Hinder enemies.
• , or to chill enemies.
  • Can be linked with for increased chill effect
• to create Consecrated Ground
• , , or for passive corpse disposal and minion buffing
• to escape melee range (could backfire).
• Defensive curses such as ,
• Defensive golems such as , .
  • Can be linked with

Other:

• for builds that die often.
• is often used in AFK boss kill attempts such as Uber Elder or Sirus.

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.
• (As of Version 1.2.2 CWDT will only trigger Ball Lightning in this example, Ball Lightning will then only trigger Hextouch if the supported curse is above the CWDT level threshold.)

With self damaging mechanics it is possible to cause spells created from CWDT to proc CWDT again creating a loop. Some possibilities are:

• Scold's Bridle
  • Pros: stable output; you can tune proc rate by changing mana cost; only one item required
  • Cons: requires fast recovery to mitigate damage taken, otherwise you can kill yourself in hideout just by testing skills. Usually Agnostic Pathfinder with mana flask, Clarity watcher's eye mod, Battle Rouse.
• Heartbound Loop
  • Pros: stable output
  • Cons: same as Scold's + huge waste of jewel sockets
• Eye of Innocence
  • Pros: great recovery (at worst you take damage as frequently as you gain HP back); many recovery options: Vitality mod, Discipline mod, Ngamahu's Sign, Razor of the Seventh Sun, Shaper rings
  • Cons: 100% chance to ignite forces passive tree/ascendancy choices; easier to get best proc rates against packs than against single targets
• Replica Tulfall
  • Pros: stable recovery, you can adapt to bad map mods by changing number of socketed Powerlessness jewels
  • Cons: Pathfinder mana or tons of unique items to get HP recovery, better proc rates against packs than single target
• Gluttony or Hiltless
  • Pros: one item
  • Cons: requires external life recovery, low trigger rate (enough to proc Vengeance)
• Storm Secret
• Doedre's Elixir
• Forbidden Rite

Quick reference chart of commonly used spell gems and their maximum allowed level to be supported by each level of CWDT:

Level	Damage Threshold	Damage Modifier	Max level of spell gems	(Endurance charge bonus)	(additional armour)									Golem (any)
1	528	-70%	38	3 (106%)	10 (282)	4	5	10	7	4	7	3	5	3
2	583	-66%	40	4 (109%)	11 (328)	5	6	11	8	5	8	4	6	4
3	661	-62%	42	5 (112%)	11 (328)	6	7	11	8	6	8	5	7	5
4	725	-58%	44	6 (115%)	12 (378)	7	7	12	9	7	9	6	7	6
5	812	-54%	46	7 (118%)	12 (378)	8	8	12	10	8	10	7	8	7
6	897	-50%	48	8 (121%)	13 (433)	9	9	13	10	9	10	8	9	8
7	1003	-46%	50	9 (124%)	13 (433)	10	10	13	11	10	11	9	10	9
8	1107	-42%	52	10 (127%)	14 (495)	11	11	14	12	11	12	10	11	10
9	1221	-38%	54	11 (130%)	14 (495)	12	12	14	12	12	12	11	12	11
10	1354	-34%	56	12 (133%)	15 (545)	13	13	15	13	13	13	12	13	12
11	1485	-30%	58	13 (136%)	16 (599)	14	14	16	14	14	14	13	14	13
12	1635	-26%	60	14 (139%)	16 (599)	15	15	16	15	15	15	14	15	14
13	1804	-22%	62	15 (142%)	17 (657)	16	16	17	16	16	16	15	16	15
14	1980	-18%	64	16 (145%)	18 (719)	17	17	18	17	17	17	16	17	16
15	2184	-14%	65	16 (145%)	18 (719)	17	17	18	17	17	17	16	17	16
16	2394	-10%	66	17 (148%)	18 (719)	18	18	18	18	18	18	17	18	17
17	2621	-6%	67	17 (148%)	19 (786)	18	18	19	18	18	18	17	18	17
18	2874	-2%	68	18 (151%)	19 (786)	19	19	19	19	19	19	18	19	18
19	3142	+2%	69	19 (154%)	19 (786)	19	19	19	19	19	19	19	19	19
20	3272	+6%	70	20 (157%)	20 (858)	20	20	20	20	20	20	20	20	20
21	3580	+10%	72	21 (160%)	21 (909)	21	21	21	21	21	21	21	21	21
22	3950	+14%	74	22 (163%)	22 (962)	22	22	22	22	22	22	22	22	22
23	4350	+18%	76	23 (166%)	23 (1018)	23	23	23	23	23	23	23	23	23

Cats when Damage Taken

Cats spawned by Cats when Damage Taken

Cats when Damage Taken was a trigger gem available only on April 1, 2015 as an April Fool's joke. 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.

Version history

Version	Changes
3.15.0	Now has a 250% Cost and Reservation Multiplier.
Unknown	(Not documented in patch notes) the Divergent alternate gem quality has changed to Supported Skills require 1% reduced amount of Damage taken to Trigger
3.12.0	Now has alternative gem quality: Anomalous: Supported Skills have 1% increased Skill Effect Duration (per 1% quality) Divergent: 1% more Damage required to Trigger (per 1% quality)
2.0.0	Enduring Cry is now a Warcry instead of a spell, therefore it can't be cast anymore.
1.3.1g	Fixed a bug with the trigger gems that cause spells to automatically cats on various conditions.
1.3.1	Spells triggered by Cast on Damage Taken have had their damage reduced by 25%.
1.3.0	Trigger gems are now classified as Trigger.
1.2.2	Gems may now only be supported by a single trigger gem, gems supported by multiple trigger gems will be disabled.
1.0.1	The level requirement of gems augmented by Cast on Damage Taken may not exceed the level requirement of the Cast on Damage Taken gem.
1.0.0f	Cooldown of 250ms added.
1.0.0	Cast when Damage Taken has been added to the game.