Arc

ArcSpell, Chaining, Lightning
Mana Cost: (8-23)
Cast Time: 0.70 sec
Critical Strike Chance: 5.00%
Effectiveness of Added Damage: 80%Requires Level 12An arc of lightning stretches from the caster to a targeted enemy and chains on to other nearby enemies. Each time the main beam chains it will also chain to a second enemy, but that secondary arc cannot chain further.Per 1% Quality:1Superior2Anomalous3Divergent4Phantasmal0.5% chance to Shock enemies1% increased Chaining range0.5% increased Damage for each time this Skill has Chained1% reduced Enemy Stun ThresholdDeals (6-133) to (33-754) Lightning Damage
10% chance to Shock enemies
Chains +(4-7) Times
(10-29)% increased Effect of Lightning Ailments
15% more Damage for each remaining ChainPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket.Acquisition
Level: 12Purchase Costs

Normal

1x Orb of Transmutation

Sell Price
1x Scroll FragmentMiscellaneous
Item class: Active Skill Gems
Metadata ID: Metadata/Items/Gems/SkillGemArc

For the Vaal-themed counterpart, see Vaal Arc.

Arc is a lightning spell that creates a chaining pulse.

Skill functions and interactions

• Since it is not a projectile, Arc cannot fork or pierce, and it cannot be supported with Lesser Multiple Projectiles SupportLesser Multiple Projectiles SupportSupport, Projectile
  Icon: l
  Mana Multiplier: 140%Requires Level 8Supports projectile skills.Per 1% Quality:123Supported Skills have 0.5% increased Attack Speed
  Supported Skills have 0.5% increased Cast SpeedSupported Skills have 1% reduced Mana Cost
  Supported Skills have 0.5% increased Projectile SpeedProjectiles Fired by Supported Skills have 1% increased Projectile spreadSupported Skills fire 2 additional Projectiles
  Supported Skills deal (15-6)% less Projectile DamageThis 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 Active Skill Gem you wish to augment. Right click to remove from a socket. or Greater Multiple Projectiles SupportGreater Multiple Projectiles SupportSupport, Projectile
  Icon: P
  Mana Multiplier: 165%Requires Level 38Supports projectile skills.Per 1% Quality:1Superior2Anomalous3DivergentSupported Skills have 0.5% increased Attack Speed
  Supported Skills have 0.5% increased Cast SpeedSupported Skills have 1% reduced Mana Cost
  Supported Skills have 0.5% increased Projectile SpeedProjectiles Fired by Supported Skills have 1% increased Projectile spreadSupported Skills fire 4 additional Projectiles
  Supported Skills deal (35-26)% less Projectile DamageThis 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 Active Skill Gem you wish to augment. Right click to remove from a socket..
• Supporting Arc with Chain SupportChain SupportSupport, Chaining, Projectile
  Icon: c
  Mana Multiplier: 150%Requires Level 38Supports projectile skills, and any other skills that chain.Per 1% Quality:123Supported Skills have 1% increased Projectile SpeedSupported Skills have 1% increased Chaining rangeProjectiles Fired by Supported Skills have 4% chance not to Pierce EnemiesSupported Skills Chain +2 times
  Supported Skills deal (30-11)% less Damage with HitsThis 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 Active Skill Gem you wish to augment. Right click to remove from a socket. will result in additional chains.
• Arc will chain to a random target within a specified radius centered on last target struck. Arc cannot chain back to the same target immediately, and must bounce one more time before chaining to the previous target. Because Arc also forks with each bounce, it requires 4 grouped enemies to bounce back to the original.
• Arc will target the nearest enemy within range if not cast on an enemy.
• 15% More Damage for each remaining chain is additive with itself, not multiplicative. When hitting a single enemy, the skill will consider ALL chains are remaning and when hitting multiple enemies, the first one will be considered to be with all chains remaining, the second with 1 less chain remaining and so on.
• Can be used in left mouse button slot to cast and move.

Gem level progression

Level			Mana Cost	Lightning Damage	Chains	Shock Effect	Exp.	Total Exp.
1	12	33	8	6 to 33	+4	N/A	0	0
2	15	39	9	7 to 41	+4	N/A	15,249	15,249
3	19	48	10	9 to 54	+4	N/A	41,517	56,766
4	23	56	11	12 to 70	+4	N/A	81,983	138,749
5	27	64	12	16 to 89	+4	N/A	147,968	286,717
6	31	73	13	20 to 112	+5	N/A	250,557	537,274
7	35	81	14	25 to 139	+5	N/A	405,086	942,360
8	38	88	15	29 to 163	+5	N/A	447,718	1,390,078
9	41	94	16	34 to 191	+5	N/A	615,318	2,005,396
10	44	100	16	39 to 223	+5	N/A	834,639	2,840,035
11	47	106	17	46 to 258	+6	N/A	1,570,760	4,410,795
12	50	113	18	53 to 299	+6	N/A	1,633,987	6,044,782
13	53	119	19	61 to 346	+6	N/A	2,151,030	8,195,812
14	56	125	19	70 to 399	+6	N/A	2,812,189	11,008,001
15	59	132	20	81 to 458	+6	N/A	5,099,360	16,107,361
16	62	138	21	93 to 526	+7	N/A	9,400,731	25,508,092
17	64	142	21	102 to 577	+7	N/A	15,273,366	40,781,458
18	66	146	22	111 to 631	+7	N/A	26,286,582	67,068,040
19	68	151	22	122 to 690	+7	N/A	62,890,590	129,958,630
20	70	155	23	133 to 754	+7	N/A	212,046,017	342,004,647
21	72	159	24	145 to 824	+8	N/A	N/A	N/A
22	74	N/A	24	159 to 900	+8	N/A	N/A	N/A
23	76	N/A	25	173 to 982	+8	N/A	N/A	N/A
24	78	N/A	25	189 to 1070	+8	N/A	N/A	N/A
25	80	N/A	26	206 to 1167	+8	N/A	N/A	N/A
26	82	N/A	26	224 to 1271	+9	N/A	N/A	N/A
27	84	N/A	27	244 to 1384	+9	N/A	N/A	N/A
28	86	N/A	27	266 to 1506	+9	N/A	N/A	N/A
29	88	N/A	28	289 to 1639	+9	N/A	N/A	N/A
30	90	N/A	28	314 to 1782	+9	N/A	N/A	N/A
31	91	N/A	28	328 to 1858	+10	N/A	N/A	N/A
32	92	N/A	29	342 to 1937	+10	N/A	N/A	N/A
33	93	N/A	29	356 to 2019	+10	N/A	N/A	N/A
34	94	N/A	29	371 to 2105	+10	N/A	N/A	N/A
35	95	N/A	29	387 to 2193	+10	N/A	N/A	N/A
36	96	N/A	30	403 to 2286	+11	N/A	N/A	N/A
37	97	N/A	30	420 to 2382	+11	N/A	N/A	N/A
38	98	N/A	30	438 to 2482	+11	N/A	N/A	N/A
39	99	N/A	30	456 to 2586	+11	N/A	N/A	N/A
40	100	N/A	31	475 to 2694	+11	N/A	N/A	N/A

Item acquisition

Upgrade paths

This item can be acquired through the following upgrade paths or vendor recipes:

Amount	Ingredient	General Notes	Type
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	Automatic
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	Automatic
3	Gemcutter's PromiseGemcutter's Promise3Superior Gem 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 superior gem (Q20)	Automatic

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.

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

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.

Version history

Version	Changes
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 Mana Cost: (8-23) Cast Time: 0.70 sec Critical Strike Chance: 5.00% Effectiveness of Added Damage: 80%Requires Level 12An arc of lightning stretches from the caster to a targeted enemy and chains on to other nearby enemies. Each time the main beam chains it will also chain to a second enemy, but that secondary arc cannot chain further.Per 1% Quality:1Superior2Anomalous3Divergent4Phantasmal0.5% chance to Shock enemies1% increased Chaining range0.5% increased Damage for each time this Skill has Chained1% reduced Enemy Stun ThresholdDeals (6-133) to (33-754) Lightning Damage 10% chance to Shock enemies Chains +(4-7) Times (10-29)% increased Effect of Lightning Ailments 15% more Damage for each remaining ChainPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. and Vaal ArcVaal ArcVaal, Spell, Chaining, Lightning, Duration Souls Per Use: 25 (N) / Can Store 1 Use(s) Soul Gain Prevention: 0.001 sec Cast Time: 0.80 sec Critical Strike Chance: 5.00% Effectiveness of Added Damage: 180%Requires Level 12A shocking arc of lightning stretches from the caster to a targeted enemy and chains to other nearby enemies. Each time the beam chains it will also chain simultaneously to a second enemy, but no enemy can be hit twice by the beams. Also grants a buff making you lucky when damaging enemies with Arc for a short duration.Per 1% Quality:11.5% increased Duration of Lightning AilmentsBase duration is 4 seconds Deals (38-924) to (64-1539) Lightning Damage 100% chance to Shock enemies Chains +(5-9) Times 100% increased Effect of Lightning Ailments 100% increased Duration of Lightning Ailments 15% more Damage for each remaining Chain Modifiers to Buff Duration also apply to this Skill's Soul Gain Prevention CorruptedPlace 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.