Arc

ArcSpell, Projectile, Lightning, Chaining
Tier: 5
Level: (1-20)
Cost: (8-81) Mana
Cast Time: 1.10 sec
Critical Strike Chance: 9.00%An arc of Lightning stretches from the caster to a targeted enemy and Chains on to other nearby enemies. Consumes a Lightning Infusion if possible to deal more damage and Chain further.Deals (1-20) to (13-386) Lightning Damage
Chains (5-9) times
50% more Magnitude of Shock inflicted
Chains 6 additional times when Lightning Infused
200% more damage when Lightning Infused

Additional Effects From 1-20% Quality:
Chains (0.1-2) timesSkills can be managed in the Skills Panel.

Acquisition
Drop restricted
It can be obtained by engraving an Uncut Skill Gem.Metadata
Item class: Skill Gem
Metadata ID: Metadata/Items/Gems/SkillGemArc

Arc is a lightning spell skill that fires a lightning projectile forward, which chains to nearby enemies on hit. If you have a Lightning Infusion, it is consumed to add more damage and additional chains.

Skill functions and interactions

Arc can't shock.

Gem level progression

Level			Mana Cost	Lightning Damage	Chains
1	0	0	8	1 to 13	—
2	3	9	9	1 to 17	—
3	6	14	11	1 to 24	—
4	10	21	12	2 to 31	—
5	14	28	14	2 to 39	—
6	18	35	17	3 to 48	—
7	22	41	19	3 to 58	—
8	26	48	22	4 to 69	—
9	31	57	24	4 to 82	—
10	36	65	28	5 to 96	—
11	41	74	31	6 to 112	—
12	46	82	35	7 to 130	—
13	52	92	39	8 to 151	—
14	58	103	44	9 to 174	—
15	64	113	49	10 to 199	—
16	66	116	54	12 to 228	—
17	72	126	60	14 to 261	—
18	78	137	67	16 to 298	—
19	84	147	74	18 to 339	—
20	90	157	81	20 to 386	—

Recommended support gems

The following support gems are recommendations by GGG as listed in-game, and do not necessarily reflect optimal combinations or the views of the wiki.

Gem tier	Support gems
I	Chain IChain ISupport, Projectile, Chaining Category: Chain Tier: 1Support Requirements: +5 DexSupports Projectile skills and any other skills that Chain, causing them to Chain additional times.Supported Skills Chain +1 times Supported Skills Chain 100% more times Supported Skills deal 50% less Damage with HitsPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.	Controlled DestructionControlled DestructionSupport, Spell Category: Controlled Destruction Tier: 1Support Requirements: +5 IntSupports Spells that Hit enemies, boosting their damage but preventing them from dealing Critical Hits.Supported Spells deal 25% more Hit Damage Supported Skills cannot deal Critical HitsPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.	UnleashUnleashSupport, Spell Category: Unleash Tier: 1 Cost & Reservation Multiplier: 150%Support Requirements: +5 IntSupports Spells you cast yourself, making their effect reoccur when cast. Cannot support Channelling Skills or Skills with a Cooldown.Supported Spells gain a Seal every 200% of cast time, to a maximum of 2 Seals Supported Spells are Unsealed when cast, and their effects Reoccur for each Seal lost Supported Skills deal 50% less Damage when ReoccurringPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.
II	Lightning PenetrationLightning PenetrationSupport, Lightning Category: Lightning Penetration Tier: 2 Cost & Reservation Multiplier: 120%Support Requirements: +5 DexSupports any skill that Hits enemies, making those Hits Penetrate enemy Lightning resistance.Supported Skills Penetrate 30% Lightning ResistancePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.	Mana FlareMana FlareSupport, Spell, AoE, Trigger, Fire, Critical Tier: 2Support Requirements: +5 IntSupports any Spell that Hits enemies, causing it to trigger a Mana Flare on Critical Hit. The Mana Flare consumes your Mana to deal Fire damage. Cannot support the skills of Minions.Support Supported Skills trigger Mana Flare on Critical Hit Mana Flare Cooldown Time: 1.00s Cast Time: 1.00s Critical Hit Chance: 7.00% Consumes 25% of current Mana to deal that much Fire damage Flare radius is 2 metresPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.	Shock ConductionShock ConductionSupport, AoE, Lightning Category: Shock Conduction Tier: 2 Cost & Reservation Multiplier: 120%Support Requirements: +5 IntSupports any skill that Hits enemies, giving it a chance to also Shock nearby enemies when you Shock an enemy.Shocking Hits from supported Skills have a 50% chance to also Shock enemies in a 2.5 metre radiusPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.
III	DeliberationDeliberationSupport Category: Deliberation Tier: 3Support Requirements: +5 DexSupports skills that can be used while moving, causing you to move slower while using them, but granting more damage in exchange.Supported Skills deal 20% more Damage 30% more Movement Speed penalty while using Supported SkillsPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.	Elemental DischargeElemental DischargeSupport, Spell, AoE, Trigger, Lightning, Cold, Fire, Payoff Tier: 3Support Requirements: +5 IntSupports any Spell that Hits enemies, causing it to consume Elemental Ailments on hit to trigger an Elemental Discharge. Cannot support the skills of Minions.Support Supported Skills Cannot inflict Freeze, Shock or Ignite Supported Skills Consume Freeze, Shock and Ignite on hit to trigger Elemental Discharge Elemental Discharge Cooldown Time: 1.00s Cast Time: 1.00s Critical Hit Chance: 10.00% Consuming Freeze deals 80% to 120% of your Intelligence as Cold Damage Consuming Ignite deals 40% to 60% of your Intelligence as Fire Damage Consuming Shock deals 1% to 120% of your Intelligence as Lightning Damage Discharge radius is 2 metresPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.	Wildshards IWildshards ISupport, Spell, Projectile Category: Additional Projectiles Tier: 3 Cost & Reservation Multiplier: 120%Support Requirements: +5 IntSupports Projectile Spells. Supported Spells have a chance to fire many additional Projectiles in a circle.Supported Skills have a 20% chance to fire 8 additional Projectiles in a circlePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.
IV	Lightning ExposureLightning ExposureSupport, Lightning, Duration Category: Lightning Exposure Tier: 4 Cost & Reservation Multiplier: 120%Support Requirements: +5 DexSupports any skill that Hits enemies, causing it to inflict Exposure when inflicting Shock.Supported Skills inflict Exposure for 8 seconds on Shocking a targetPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.	Nova ProjectilesNova ProjectilesSupport, Projectile Category: Additional Projectiles Tier: 4Support Requirements: +5 DexSupports Projectile Skills, making them fire extra Projectiles in a circle, at the cost of Damage. Does not support Skills which rain down Projectiles from above.Supported Skills fire 4 additional Projectiles Supported Skills fire Projectiles in a circle Supported Skills deal 40% less DamagePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.	Rapid Casting IIRapid Casting IISupport, Spell Category: Rapid Casting Tier: 4Support Requirements: +5 IntSupports Spells, causing them to cast faster.Supported Skills have 20% increased Cast SpeedPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.
V	Chain IIIChain IIISupport, Projectile, Chaining Category: Chain Tier: 5Support Requirements: +5 DexSupports Projectile skills and any other skills that Chain, causing them to Chain additional times.Supported Skills Chain 200% more times Supported Skills deal 40% less Damage with HitsPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.	Lightning MasteryLightning MasterySupport, Lightning Category: Mastery Tier: 5Support Requirements: +5 IntSupports Lightning skills, granting them an additional level. Does not support skills which do not have levels.+1 to Level of Supported Lightning SkillsPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.	Projectile Acceleration IIIProjectile Acceleration IIISupport, Projectile Category: Projectile Speed Tier: 5 Cost & Reservation Multiplier: 120%Support Requirements: +5 DexSupports Projectile skills, making those Projectiles travel faster, and causing increases and reductions to Projectile speed to also apply to Damage.Increases and reductions to Projectile speed also apply to Projectile Damage with Supported Skills Supported Skills have 40% more Projectile SpeedPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple Support Gems of the same Category socketed within one Skill.

Item acquisition

Arc has restrictions on where or how it can drop.

It can be obtained by engraving an Uncut Skill Gem.

Alternate skill effects

Arc has the following alternate skill effects:

Item	Description

Version history

Version	Changes
0.3.0	The base damage scaling of all player spell and secondary damage skills has been tweaked to scale better in the late game. Arc: Is now a Projectile. It no longer causes explosions against shocked enemies and is no longer a payoff skill. It now chains 6-9 times at Gem levels 5-20 (previously 5-8). It now has 50% more shock magnitude, and can now consume a lightning infusion to chain additional times and deal more damage. Now deals 2-39 damage at Gem level 5 (previously 5-31), scaling up to 20-386 damage at gem level 20 (previously 49-277). Quality now provides Chains +0-2 additional times (previously 0- 2% more Damage for each remaining Chain). Removed "Barrageable" and "AoE" gem tags. [Undocumented]
0.2.1	Added "Barrageable" gem tag. [Undocumented]
0.2.0f	Improved the visual effects of Arc's explosions on hitting a shocked target.
0.2.0e	Arc now releases damaging pulses when Shocked enemies are Hit, but can no longer Shock. It does not consume the Shock. The Arc now deals 9 to 51 at Gem level 1 (previously 9 to 50), scaling up to 82 to 462 at Gem level 20 (previously 72 to 410). The Pulse deals 5 to 31 Lighting Damage at Gem level 1, scaling up to 49 to 277 at Gem level 20, and has a radius of 1.5 metres. Added "AoE" and "Payoff" gem tags.[Undocumented]
0.2.0	Many Skills have had their base damage and/or damage growth per level rebalanced. Most of these changes are not specifically mentioned below as the changes are too widespread. Arc no longer deals more Damage for each remaining Chain, and Chains 6-8 times at Gem levels 5-20 (previously 2-5). Quality now provides 0-2% more Damage for each remaining Chain (previously 0-5%).
0.1.0	Introduced to the game.