Arc

ArcSpell, Chaining, Lightning
Level: (1-20)
Cost: (8-23) Mana
Cast Time: 0.70 sec
Critical Strike Chance: 6.00%
Effectiveness of Added Damage: 120%Requires Level 12An arc of lightning reaches from the caster to a targeted enemy and chains to other enemies, but not immediately back. Each time the arc chains, it will also chain a secondary arc to another enemy that the main arc has not already hit, which cannot chain further.Deals (6-198) to (32-1122) Lightning Damage
Chains +(4-7) Times
15% more Damage with Hits and Ailments for each remaining Chain

Additional Effects From 1-20% Quality:
Chains +(0.05-1) TimesPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket.

Acquisition
Drop level: 12Vendor Offer
1x Scroll FragmentMetadata
Item class: Skill Gem
Metadata ID: Metadata/Items/Gems/SkillGemArc

Arc is a lightning spell that creates a chaining pulse of electricity.

Skill functions and interactions

• Chain: Arc deals 15% more damage per remaining chain. Arc gains base chains from gem level, and additional sources of chain such as Chain SupportChain SupportSupport, Chaining, Projectile
  Icon: c
  Level: (1-20)
  Cost & Reservation Multiplier: 150%Requires Level 38Supports projectile skills, and any other skills that chain.Supported Skills Chain +2 times
  Supported Skills deal (30-11)% less Damage with Hits
  
  Additional Effects From 1-20% Quality:
  Supported Skills have (0.5-10)% increased Chaining rangeThis is a Support Gem. It does not grant a bonus to your character, but to skills in sockets connected to it. Place into an item socket connected to a socket containing the Skill Gem you wish to augment. Right click to remove from a socket. are also taken into account for this bonus.
  • Every time Arc chains, a secondary Arc is created that hits an additional nearby enemy. This secondary Arc cannot chain further.
  • Arc remembers the last two enemies hit by the main Arc, and will not hit these enemies again. This means at least 3 enemies are required before the main Arc can hit the same enemy twice.
• The lucky buff from Vaal Arc only affects Arc's hit damage and not ailments.

Gem level progression

Level			Mana Cost	Lightning Damage	Chains	Exp.	Total Exp.
1	12	33	8	6 to 32	+4	0	0
2	15	39	9	7 to 41	+4	15249	15249
3	19	48	10	10 to 56	+4	41517	56766
4	23	56	11	13 to 75	+4	81983	138749
5	27	64	12	17 to 98	+4	147968	286717
6	31	73	13	22 to 127	+5	250557	537274
7	35	81	14	29 to 162	+5	405086	942360
8	38	88	15	34 to 194	+5	447718	1390078
9	41	94	16	41 to 232	+5	615318	2005396
10	44	100	16	49 to 276	+5	834639	2840035
11	47	106	17	58 to 327	+6	1570760	4410795
12	50	113	18	68 to 387	+6	1633987	6044782
13	53	119	19	81 to 457	+6	2151030	8195812
14	56	125	19	95 to 538	+6	2812189	11008001
15	59	132	20	111 to 631	+6	5099360	16107361
16	62	138	21	131 to 740	+7	9400731	25508092
17	64	142	21	145 to 822	+7	15273366	40781458
18	66	146	22	161 to 912	+7	26286582	67068040
19	68	151	22	179 to 1012	+7	62890590	129958630
20	70	155	23	198 to 1122	+7	212046017	342004647
21	72	159	24	219 to 1242	+8	N/A	N/A
22	74	N/A	24	243 to 1375	+8	N/A	N/A
23	76	N/A	25	269 to 1522	+8	N/A	N/A
24	78	N/A	25	297 to 1683	+8	N/A	N/A
25	80	N/A	26	328 to 1859	+8	N/A	N/A
26	82	N/A	26	362 to 2054	+9	N/A	N/A
27	84	N/A	27	400 to 2268	+9	N/A	N/A
28	86	N/A	27	442 to 2503	+9	N/A	N/A
29	88	N/A	28	487 to 2761	+9	N/A	N/A
30	90	N/A	28	537 to 3044	+9	N/A	N/A
31	91	N/A	28	564 to 3196	+10	N/A	N/A
32	92	N/A	29	592 to 3356	+10	N/A	N/A
33	93	N/A	29	622 to 3522	+10	N/A	N/A
34	94	N/A	29	652 to 3697	+10	N/A	N/A
35	95	N/A	29	685 to 3880	+10	N/A	N/A
36	96	N/A	30	719 to 4072	+11	N/A	N/A
37	97	N/A	30	754 to 4273	+11	N/A	N/A
38	98	N/A	30	791 to 4483	+11	N/A	N/A
39	99	N/A	30	830 to 4703	+11	N/A	N/A
40	100	N/A	31	871 to 4934	+11	N/A	N/A

Gem quality

Type	Additional Effects per 1-20% Quality	Weight
Superior	Chains +(0.05-1) Times	1

Item acquisition

Arc can drop anywhere.

Recipes

Arc can be created from the following recipes:

Amount	Part	Description	Meta
13	The CataclysmThe Cataclysm13Level 21 Spell Gem CorruptedThe mighty warriors traded in blows, the nimble archers in arrows, yet it was the brazen thaumaturgists who would bring catastrophe to all.	Random corrupted level 21 Spell gem	A
6	The FoxThe Fox6Level 20 Gem"Masters of wit, strength and cunning. To survive the harsh winters, you must be like the fox." - Ezomyte Proverb	Random level 20 gem	A
3	Gemcutter's PromiseGemcutter's Promise3Gem Quality: +20%"I swore to use my position to help the people. What good is power when it just accumulates on the already-powerful?" - Erasmus, Imperial Gemcutter	Random gem with 20% quality	A
1	Gemcutter's IncubatorGemcutter's IncubatorStack Size: 10Adds an incubated Quality Gem item to an equippable item Item drops after killing {0} monstersRight click this item then left click an item to apply it. The Incubated item drops after killing a specific number of monsters.	Random gem with 1–20% quality	A
1	The VoidThe Void1Reach into the Void and claim your prize.	Random divination card set exchange	A

Quest reward

This item is given as a quest reward for the following quests:

Class →	Witch	Shadow	Ranger	Duelist	Marauder	Templar	Scion
Quest ↓
The Siren's Cadence Act 1	✓	✗	✗	✗	✗	✗	✗

Vendor reward

This item can be bought at the listed NPC vendors, after completing the following quests:

Class →	Witch	Shadow	Ranger	Duelist	Marauder	Templar	Scion
Quest ↓
The Siren's Cadence Act 1 Nessa	✓	✓	✗	✗	✗	✓	✗
A Fixture of Fate Act 3 Siosa	✓
Fallen from Grace Act 6 Lilly Roth	✓

Related helmet enchantments

The following helmet enchantments affect Arc.

Note that helmet enchantments are no longer obtainable since version 3.23.0 and can only be obtained in permanent leagues as already enchanted items from before this patch.

Name		Labyrinth	Stats	Spawn Weighting
Enchantment Arc Damage 1	66	Merciless Labyrinth	25% increased Arc Damage	helmet 100
Enchantment Arc Damage 2	75	Eternal Labyrinth	40% increased Arc Damage	helmet 75
Enchantment Arc Damage Per Chain 1	66	Merciless Labyrinth	Arc deals 8% increased Damage for each time it has Chained	helmet 100
Enchantment Arc Damage Per Chain 2	75	Eternal Labyrinth	Arc deals 12% increased Damage for each time it has Chained	helmet 75
EnchantmentArcNumOfAdditionalProjectilesInChain1	66	Merciless Labyrinth	Arc Chains an additional time	helmet 0
Enchantment Arc Num Of Additional Projectiles In Chain 1	75	Eternal Labyrinth	Arc Chains an additional time	helmet 75
Enchantment Arc Shock Chance 1	66	Merciless Labyrinth	Arc has +20% chance to Shock	helmet 100
Enchantment Arc Shock Chance 2	75	Eternal Labyrinth	Arc has +30% chance to Shock	helmet 75

Alternate skill effects

Arc has the following alternate skill effects:

Item	Effect(s)
Automaton Arc EffectAutomaton Arc EffectSkill Gem EffectYour Arc becomes an Automaton Effect.	Your Arc becomes an Automaton Effect.
Celestial Arc EffectCelestial Arc EffectSkill Gem EffectYour Arc becomes a Celestial Effect.	Your Arc becomes a Celestial Effect.
Purple ArcPurple ArcSkill Gem EffectYour Arc becomes a Purple Effect.	Your Arc becomes a Purple Effect.
Radiant Arc EffectRadiant Arc EffectSkill Gem EffectYour Arc becomes a Radiant Effect.	Your Arc becomes a Radiant Effect.

Version history

Version	Changes
3.23.0	Now has a base Critical Strike Chance of 6% (previously 5%). It no longer has 10% chance to Shock enemies, or provides 10-29% increased Effect of Lightning Ailments. It now has 15% more Damage with Hits and Ailments for each remaining Chain at all gem levels (previously more Damage for each remaining Chain). Quality now causes the skill to Chain +0-1 Times, instead of providing a 0-10% chance to Shock enemies.
3.17.0	Arc now deals 6 to 32 Lightning Damage at gem level 1 (previously 6 to 33), up to 198 to 1122 at gem level 20 (previously 133 to 754). Now has 120% Effectiveness of Added Damage at all gem levels (previously 80%).
3.11.0	The visual effects have been improved.
3.9.0	The range at which Arc can chain to another enemy is now 35 units (from 25). Arc has received visual improvements.
3.6.2	Arc's effect now visually hits monsters more centrally.
3.6.0	Mana Cost at gem level 1 is now 8 (was 9). Mana Cost at gem level 20 is now 23 (was 26). Now has a cast time of 0.7 seconds (from 0.8). Now deals 6 to 33 Lightning damage at gem level 1 (from 7 to 37) and 133 to 754 Lightning damage at gem level 20 (from 152 to 862). Now has an added damage effectiveness of 80% (from 90%). Lowered the range at which Arc can chain from 50 units to 25 units.
3.3.0	Now has an added damage effectiveness of 90% (up from 70%). Now deals 7-37 lightning damage at gem level 1 (up from 2-35), up to 152-862 lightning damage at gem level 20 (up from 47-886). Now deals 15% more damage for each remaining chain. Can now split to an extra enemy whenever it chains. These splits cannot then chain. Chains 4 times at level 1, up to 7 times at level 20.
3.0.0	Arc now has 10% increased Shock Effect at gem level 1, gaining 1% per gem level.
2.1.0	Damage increased by around 20% higher at level 20. In addition to having more damage, Arc now increases in number of chains more often as it levels up. At level 20, it chains seven times. Previously this was five.
2.0.0	Damage reduced slightly at all levels. At player level 68, it should deal approximately 8% less damage.
1.3.1	(PvP) Arc damage has been increased by 5%. The total reduction is now 5% (up from 10% reduction previously).
1.2.0	We have reduced the damage by 15% at all levels. Got +1% to critical hit chance bringing it to 5%
1.1.2	ArcArcSpell, Chaining, Lightning Level: (1-20) Cost: (8-23) Mana Cast Time: 0.70 sec Critical Strike Chance: 6.00% Effectiveness of Added Damage: 120%Requires Level 12An arc of lightning reaches from the caster to a targeted enemy and chains to other enemies, but not immediately back. Each time the arc chains, it will also chain a secondary arc to another enemy that the main arc has not already hit, which cannot chain further.Deals (6-198) to (32-1122) Lightning Damage Chains +(4-7) Times 15% more Damage with Hits and Ailments for each remaining Chain Additional Effects From 1-20% Quality: Chains +(0.05-1) TimesPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. and Vaal ArcVaal ArcSpell, Chaining, Vaal, Lightning, Duration Level: (1-20) Souls Per Use: 25 Can Store 1 Use(s) Soul Gain Prevention: 2 sec Cast Time: 0.70 sec Critical Strike Chance: 6.00% Effectiveness of Added Damage: 220%Requires Level 12A shocking arc of lightning reaches from the caster to a targeted enemy and chains to other enemies. Each time the arc chains from an enemy, it will do so simultaneously to two further enemies, but never to enemies that have already been hit by any of these chains. Also grants a buff making your Arc damage lucky for a short duration.Deals (38-924) to (64-1539) Lightning Damage 100% increased Duration of Lightning Ailments Base duration is 4.00 seconds 100% chance to Shock enemies Chains +(5-9) Times 15% more Damage with Hits and Ailments for each remaining Chain 100% increased Effect of Lightning Ailments Additional Effects From 1-20% Quality: Chains +(0.05-1) TimesCorruptedPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. have had their damage increased by 60%. Arc and Vaal Arc can now no longer chain back to the same target immediately, but must now bounce one more time. Arc now increases in chain counts as the gem increases in level.
1.0.0	Reduced the mana cost. Damage has been increased by around 23%.
0.11.1	Spells with Damage Effectiveness no longer have their own damage affected by Damage Effectiveness. Damage values on these skills have been updated to reflect this.
0.9.13	Arc has been added to the game.