Cast On Critical Strike Support

Cast on Critical Strike (commonly referred to as CoC) is a support gem that causes linked spells to trigger when the player scores a critical strike with the attack skill it is linked to.

Skill functions and interactions

The chance to trigger is rolled separately for each enemy that received a critical strike, so it is possible to get multiple casts on one skill use if multiple enemies get hit.

In case of multiple spells linked to one attack skill this support will roll its chance to cast for each spell sequentially with 100% chance to cast when the hit crits, rolled once against the critical strike chance, and again against the accuracy rating to make sure it has hit. In the case of a hits can't be evaded modifier, this second roll is counted as 100%.

Cooldown Time: When a supported spell is successfully cast, it and all supported spells of the same name are put on cooldown for 500 milliseconds. This means that a given spell can only trigger once per critical strike, and reduces the effect of linking multiple copies of the same spell to this support (especially when it is at a higher gem level). It is important to note that this cooldown does not apply to the gem as whole; you can trigger multiple spells within the 500 millisecond cooldown time as long as they are different.

Gem level progression

Level				More Spell Damage %	Exp.	Total Exp.
1	38	40	27	N/A	0	0
2	40	41	29	N/A	388734	388734
3	42	43	30	N/A	477437	866171
4	44	45	31	N/A	583786	1449957
5	46	47	33	N/A	710359	2160316
6	48	49	34	N/A	1355511	3515827
7	50	51	35	N/A	1138877	4654704
8	52	53	37	N/A	1368233	6022937
9	54	55	38	N/A	1638338	7661275
10	56	57	39	N/A	1956648	9617923
11	58	58	41	N/A	3655184	13273107
12	60	60	42	N/A	3017327	16290434
13	62	62	43	N/A	3576232	19866666
14	64	64	44	N/A	4231667	24098333
15	65	65	45	N/A	2395078	26493411
16	66	66	46	N/A	8421063	34914474
17	67	67	46	N/A	16159983	51074457
18	68	68	47	N/A	41170367	92244824
19	69	69	48	N/A	86794448	179039272
20	70	70	48	N/A	157405063	336444335
21	72	72	50	N/A	N/A	N/A
22	74	N/A	N/A	N/A	N/A	N/A
23	76	N/A	N/A	N/A	N/A	N/A
24	78	N/A	N/A	N/A	N/A	N/A
25	80	N/A	N/A	N/A	N/A	N/A
26	82	N/A	N/A	N/A	N/A	N/A
27	84	N/A	N/A	N/A	N/A	N/A
28	86	N/A	N/A	N/A	N/A	N/A
29	88	N/A	N/A	N/A	N/A	N/A
30	90	N/A	N/A	N/A	N/A	N/A
31	91	N/A	N/A	N/A	N/A	N/A
32	92	N/A	N/A	N/A	N/A	N/A
33	93	N/A	N/A	N/A	N/A	N/A
34	94	N/A	N/A	N/A	N/A	N/A
35	95	N/A	N/A	N/A	N/A	N/A
36	96	N/A	N/A	N/A	N/A	N/A
37	97	N/A	N/A	N/A	N/A	N/A
38	98	N/A	N/A	N/A	N/A	N/A
39	99	N/A	N/A	N/A	N/A	N/A
40	100	N/A	N/A	N/A	N/A	N/A

Strategy

Linking with other skills

At a bare minimum, a Cast On Critical Strike setup will require three gems: an attack, Cast On Critical Strike itself, and a spell to be triggered. This generally leaves at most three other supports that may be linked. If possible, the supports should both increase the number of times Cast On Critical Strike triggers, and increase the effectiveness of the triggered spells. Note that Cast On Critical Strike cannot trigger more than once per frame, so staggered hits (e.g. multiple projectiles) are preferred to simultaneous hits (e.g. most area of effect damage) which will only proc at most once per attack.

Projectile

By far the most popular family of Cast on Critical Strike setups, projectile Cast On Critical Strike focuses on the projectile keyword. Popular attacks for this purpose include:

• Spectral Throw: Naturally staggers hits, automatic pierce, allows the use of melee weapons at range.
• Barrage: Causes a large number of sequential hits per attack.
• Power Siphon: Naturally produces power charges.
• Split Arrow: Naturally large number of projectiles.
• Tornado Shot: Piercing on initial arrow(s) and produces three times as many subprojectiles.
• Frost Blades: Five projectiles plus the initial hit.
• Molten Strike: Magma balls generally hit on different frames, causing a large number of hits.
• Lightning Strike: Three projectiles plus the initial hit.

Support skills that affect both the number of hits and crits projectile attacks generate and affect projectile spells include:

• for Spectral Throw and certain spells

Useful projectile spells and their support limitations include:

• : Does not explode on pierce, fork, or chain.
• Ball Lightning: Not affected by pierce, fork, or chain; hit rate limited per cast, not per projectile.
• Ethereal Knives: Little benefit from but more from .
• Fireball: Does not explode on pierce, fork, or chain.
• Freezing Pulse: Benefits from .
• Ice Spear: Already pierces in first form.
• Spark: Less benefit from but more from .

A second spell may satisfactorily be used in place of a support.

Area of Effect

Some attacks have advantageous built-in area of effect:

• Ground Slam: The area of effect is progressive, not instant, allowing multiple casts per attack. However, it can only get one cast against a single target.

This works well with spells which have Area of Effect component, such as:

• Cold Snap
• Ice Nova
• Glacial Cascade

Support gems which can benefit this setup are:

Minion

Another possibility is to use attacks to trigger minions, which benefit from attack supports. In addition to the projectile skills listed before, we have some other good choices:

• Double Strike: Causes two hits per attack, only uses main hand when dual-wielding.
• Cyclone: Causes staggered hits rapidly.

Minions generally have poor critical strike capabilities, so critical strike supports are not as effective as they are with projectile spells. Good attack supports include:

• : While it does not increase procs much due to the splash happening on a single frame, it greatly improves minion effectiveness.
• : For Melee attacks.
• : Improves minion accuracy greatly, removes the need for accuracy on gear.
• Since patch 2.0.0, increasing gem quality on no longer grants 1% increased chance of critical strike per 1% gem quality, and instead gives a simple 1% increased accuracy per 1% gem quality. Accuracy is a desirable stat, as one cannot crit what they cannot actually hit. However, the loss of the critical strike stat granted from gem quality means this is no longer a top-tier supporting gem choice. Losing the critical strike chance affects not only the minion gem in the link; as mentioned minions have poor critical strike capabilities, and were only the minion affected there would be no noticable difference after patch 2.0.0. Of course, this is not the case, as the critical strike chance also affects the attack you are using to proc CoC (the 'trigger' spell), and any other spells to be cast on critical strike (the 'triggered' spells) in the link. This essentially results in less CoC procs overall, less damage from your trigger spell, and less critical hits from your triggered spells as well. This triple-whammy means that Additional Accuracy Support is no longer the top-tier option that it once was, with or without an attached minion and minion-buffing support gems. When considering only the minion, and ignoring any of the triggering/triggered spells & CoC proc rate, the golem/minion is likely perform better with a Faster Attacks Support instead of Additional Accuracy Support; minions will miss more, but making far more attacks per measurement of time. No longer recommended in a CoC link since patch 2.0.0 except to fill in accuracy you desperately need due to poor passive tree and/or gear options.

Most minions are severely capped in number and thus do not benefit much from the high proc rate of Cast On Critical Strike. However, there is one that works well:

Passives and gear

Since "double-dipping" on support gems is key to an effective Cast On Critical Strike setup, having a 5- or 6-link is more important than it is for most builds.

Unlike conventional attack builds, attack damage is not necessary on passives or gear, though it can be helpful in situations where the linked spells are less effective. Attack speed and critical strike chance are the two essential statistics.

Some base item types tend to have better critical hits per second than others:

1. Wands
2. Claws, Daggers
3. Sceptres, Thrusting Swords
4. Bows, Staves, 1H Swords

Possibly good uniques to use include:

Item	Perfect crits/s
Death's HarpDeath's Harp Death BowBow Quality: +20% Physical Damage: (44-49) to (116.6-129.85) Critical Strike Chance: (6.50%-7.50%) Attacks per Second: 1.32 Weapon Range: 120Requires Level 32, 107 Dex(30-50)% increased Critical Strike Chance(100-125)% increased Physical Damage 10% increased Attack Speed +50% to Global Critical Strike Multiplier Bow Attacks fire an additional ArrowThe mournful music of the strings, The creaking arch, the arrow sings. A choking cry, a rattled breath, The Reaper's Song, the Harp of Death.	9.08%
DoomfletchDoomfletch Royal BowBow Quality: +20% Physical Damage: (26.4-31.2) to (73.2-78) Critical Strike Chance: 5.00% Attacks per Second: (1.59-1.65) Weapon Range: 120Requires Level 28, 95 Dex(20-24)% increased Elemental Damage with Attack SkillsAdds (12-16) to (20-24) Physical Damage (10-14)% increased Attack Speed 60% increased Mana Regeneration Rate Gain 100% of Weapon Physical Damage as Extra Damage of a random Element"Toasted or frozen Or twitching in the light I'm not fussy And neither is Death." - Koralus Doomfletch	11.17%
Quill RainQuill Rain Short BowBow Quality: +20% Physical Damage: 13.2-35.2 Critical Strike Chance: 5.00% Attacks per Second: 3.00 Weapon Range: 120Requires Level 5, 26 Dex+(10-20) to Dexterity 100% increased Physical Damage 100% increased Attack Speed +2 Mana gained for each Enemy hit by Attacks (50-100)% increased Projectile Speed +(25-50) to Accuracy Rating 30% less Damage"The rain of a thousand quills that whittle present into past, life into death." - Rigwald of the Ezomytes	15.50%
WindripperWindripper Imperial BowBow Quality: +20% Physical Damage: 24-93.6 Elemental Damage: (48-60) to (72-90), 1 to (120-150) Critical Strike Chance: (6.50%-7.00%) Attacks per Second: (1.59-1.67) Weapon Range: 120Requires Level 66, 212 Dex(20-24)% increased Elemental Damage with Attack SkillsAdds (48-60) to (72-90) Cold Damage Adds 1 to (120-150) Lightning Damage (10-15)% increased Attack Speed (30-40)% increased Critical Strike Chance 15% increased Quantity of Items Dropped by Slain Frozen Enemies 30% increased Rarity of Items Dropped by Slain Shocked EnemiesIt hunts; as silent as falling snow, as deadly as the tempest.	17.25%
Mortem MorsuMortem Morsu Fright ClawClaw Quality: +20% Physical Damage: (23.4-26.4) to (89.7-101.2) Critical Strike Chance: 7.88% Attacks per Second: 1.80 Weapon Range: 11Requires Level 34, 61 Dex, 61 Int+20 Life gained for each Enemy hit by Attacks(75-100)% increased Physical Damage 20% increased Attack Speed 25% increased Critical Strike Chance +40% to Global Critical Strike Multiplier (10-20)% of Physical Damage Converted to Chaos Damage 25% reduced Enemy Stun Threshold with this Weapon 60% chance to Poison on HitFear blisters the heart and thins the blood. Fear squeezes lungs and sets the guts to fester. Fear is the wound left untended.	13.16%
Bino's Kitchen KnifeBino's Kitchen Knife Slaughter KnifeRune Dagger Quality: +20% Physical Damage: (72-84) to (247.2-271.2) Critical Strike Chance: (8.82%-9.45%) Attacks per Second: 1.40 Weapon Range: 10Requires Level 65, 81 Dex, 117 Int30% increased Global Critical Strike Chance30% increased Damage over Time Adds (50-60) to (120-140) Physical Damage (40-50)% increased Critical Strike Chance +(15-25)% to Global Critical Strike Multiplier +(8-12)% to Chaos Resistance On Killing a Poisoned Enemy, nearby Enemies are Poisoned and nearby Allies Regenerate 200 Life per secondCalling it poison would imply that it was even edible.	14.28%
Ungil's GaucheUngil's Gauche Boot KnifeRune Dagger Quality: +20% Physical Damage: (16-17.6) to (68-74.8) Elemental Damage: 3-30 Critical Strike Chance: 6.30% Attacks per Second: 1.59 Weapon Range: 10Requires Level 20, 31 Dex, 45 Int30% increased Global Critical Strike Chance+12% Chance to Block Attack Damage while Dual Wielding +(10-20) to Dexterity (80-100)% increased Physical Damage Adds 3 to 30 Lightning Damage 10% increased Attack Speed 50% increased Global Critical Strike ChanceUnwieldy and garish became graceful and deadly in Ungil's nimble hands.	10.47%
DivinariusDivinarius Imperial SkeanRune Dagger Quality: +20% Physical Damage: 21.6-87.6 Critical Strike Chance: 6.30% Attacks per Second: 1.50 Weapon Range: 10Requires Level 66, 95 Dex, 131 Int30% increased Global Critical Strike Chance(50-70)% increased Spell Damage +30 Life gained on Kill +10 Mana gained on Kill 10% increased Area of Effect (125-175)% increased Critical Strike Chance for Spells if you've Killed Recently +(40-60)% to Critical Strike Multiplier for Spells if you haven't Killed RecentlyDivine intervention feels better when you do it yourself.	10.47%
BrightbeakBrightbeak War HammerOne Handed Mace Quality: +20% Physical Damage: (22.1-25.35) to (52.7-60.45) Critical Strike Chance: 6.25% Attacks per Second: 2.10 Weapon Range: 11Requires Level 20, 71 Str10% reduced Enemy Stun Threshold(50-75)% increased Physical Damage 45% increased Attack Speed 25% increased Critical Strike Chance +(20-30)% to Fire Resistance +(20-30)% to Lightning Resistance"I know how to say 'faster' and 'attack' in Karui, Marak and Ezo." - Voll of Thebrus	12.19%
Doryani's CatalystDoryani's Catalyst Vaal SceptreSceptre Quality: +20% Physical Damage: (122.4-146.4) to (204-276) Critical Strike Chance: 6.00% Attacks per Second: (1.55-1.61) Weapon Range: 11Requires Level 75, 113 Str, 113 Int32% increased Elemental DamageSocketed Gems are Supported by Level 20 Elemental Proliferation Adds (65-85) to (100-160) Physical Damage (11-15)% increased Attack Speed (6-10)% increased Cast Speed (30-40)% increased Global Critical Strike Chance 0.2% of Elemental Damage Leeched as Life (80-100)% increased Elemental DamageThe result of the catalytic reaction would be either immortality for all, or death for all. It was a risk Doryani was willing to take.	10.75%
Hegemony's EraHegemony's Era Judgement StaffWarstaff Quality: +20% Physical Damage: (249.6-261.6) to (355.2-373.2) Critical Strike Chance: (7.15%-7.80%) Attacks per Second: (1.46-1.51) Weapon Range: 13Requires Level 68, 113 Str, 113 Int+20% Chance to Block Spell Damage while wielding a Staff+6% Chance to Block Attack Damage while wielding a Staff Adds (135-145) to (160-175) Physical Damage (12-16)% increased Attack Speed (10-20)% increased Critical Strike Chance +1 to Maximum Power Charges 10% chance to gain a Power Charge if you Knock an Enemy Back with Melee DamageThe right to rule demands mental acuity, a strong arm, And a tenacious sense of justice.	12.09%
DreamfeatherDreamfeather Eternal SwordOne Handed Sword Quality: +20% Physical Damage: (85.2-109.2) to (159.6-177.6) Critical Strike Chance: 5.00% Attacks per Second: (1.80-1.88) Weapon Range: 11Requires Level 66, 104 Str, 122 Dex+475 to Accuracy RatingAdds (30-50) to (65-80) Physical Damage (20-25)% increased Attack Speed +(180-200) to Evasion Rating 3% increased Movement Speed +(280-300) to Accuracy Rating 1% increased Attack Damage per 450 Evasion RatingShe dances a dance beneath the shade, The twilight shroud her only blade, Who now hears her feathersteps flowing? Beneath the stars, the moondrops glowing.	10.00%
Piscator's VigilPiscator's Vigil Tornado WandWand Quality: +20% Critical Strike Chance: (8.40%-9.10%) Attacks per Second: (1.43-1.53) Weapon Range: 120Requires Level 65, 212 Int(35-39)% increased Spell DamageNo Physical Damage (10-18)% increased Attack Speed (20-30)% increased Critical Strike Chance +(340-400) to Accuracy Rating Attacks with this Weapon have (100-115)% increased Elemental Damage Damage with Weapons Penetrates 5% Elemental Resistance"Stone still, amidst the reeds, breath fogging in the iron cold air. he sits, he waits, he watches. A piscatorial vigil, sat by the river, his cathedral, his patience his unanswered prayer." - Jojoba Mansell, bard, angler, adventurer	16.67%
TrypanonTrypanon Great MalletTwo Hand Mace Quality: +20% Physical Damage: 51.6-105.6 Critical Strike Chance: 100.00% Attacks per Second: 0.62 Weapon Range: 13Requires Level 40, 131 Str30% increased Stun Duration on Enemies50% reduced Attack Speed All Attacks with this Weapon are Critical Strikes"Though ingenius instruments have been found, it seems surgery before thaumaturgy was not so delicate." - Icius Perandus, Antiquities Collection, Item 3546	63.00%

Version history

Version	Changes
2.4.0	For Cast on Critical Strike, , MjölnerMjölner GavelOne Handed Mace Quality: +20% Physical Damage: (108-129.6) to (202-242.4) Critical Strike Chance: 5.00% Attacks per Second: 1.15 Weapon Range: 11Requires Level 60, 412 Str, 300 Int15% reduced Enemy Stun ThresholdTrigger a Socketed Lightning Spell on Hit, with a 0.15 second Cooldown Socketed Lightning Spells have no Cost if Triggered +300 Intelligence Requirement +200 Strength Requirement (80-120)% increased Physical Damage Skills Chain +1 times (30-40)% increased Lightning Damage with Attack SkillsLook the storm in the eye and you will have its respect. and Cospri's MaliceCospri's Malice Jewelled FoilOne Handed Sword Quality: +20% Elemental Damage: (80-100) to (160-200) Critical Strike Chance: 5.50% Attacks per Second: (1.73-1.82) Weapon Range: 14Requires Level 68, 212 Dex, 257 Int+25% to Global Critical Strike MultiplierTrigger a Socketed Cold Spell on Melee Critical Strike No Physical Damage Adds (80-100) to (160-200) Cold Damage Adds (40-60) to (90-110) Cold Damage to Spells (8-14)% increased Attack Speed +257 Intelligence Requirement 60% increased Critical Strike Chance against Chilled EnemiesBreathe deep, my child. Let the frigid air engulf your soul. Embrace the eternal cold, And it will embrace you back., only one skill can be triggered per trigger event. 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. Cast on Critical Strike now has a 500ms cooldown, and will now only trigger one spell per frame when you critically strike. It now has 100% chance to trigger casts when you critically strike. It now has 20% more spell damage at level 1, tapered up to 39% at level 20 (1% per level).
1.3.0	Cast on Critical Strike's cooldown has been increased from 0.01 seconds to 0.05 seconds.
1.2.0	The chance to cast has been reduced by a flat 20% at all levels.
1.0.5	Cast on Critical Strike now has a 10 millisecond cooldown. The chance to cast supported skills has been increased by a flat 20%.
1.0.0e	The Cast on Crit support gem has been renamed to Cast on Critical Strike
1.0.0	Cast on Crit has been added to the game.