Thanks to the excellent performance of Arc in 3.9, many players use arc as their league starter. Link Arc and Traps will give you huge damage, and it is very suitable for boss fight of PoE 3.9. Just try it now!

 

Quick Jump

 

Pros & Cons

  • + great map clear speed
  • + serious firepower with very low investment
  • + end-game viable (need very good reflexes for end-game though!)
  • + massive life regen (up to 20% per second and even more with Tinkerskin)
  • - Squishy as low Life pool (hard to go over 5k)
  • - Pretty slow with a wand and Flame Dash
  • - Sketchy for HC

 

Skill Tree 

Ascendancy: Pyromaniac, Perfect Crime, Chain Reaction, Explosive Expert (SC), or Born in the Shadows (HC)

Bandits: Alira or Kill All

Pantheons

The Pantheon List

  • Solaris, Arakaali is also incredibly strong with the regen we get from Ascendancy.
  • Minor: Ryslatha

Passive Tree

Path of building: https://pastebin.com/v9FqCg34

 

Skill Gems

Leveling Gems Setup

At the start you will have Explosive Trap. Use it till level 12.

At level 12 get Arc and start doing this setup:

3L: Arc-Trap Support-Multiple Traps

4L: Arc-Trap Support-Multiple Traps-Added Lightning

Level 18:

4L: Arc-Trap & Mine Damage-Trap Support-Multiple Traps

 

At level 28 start using Lightning Spire Trap in a second 4L:

4L: Lightning Spire-Added Lightning-Trap & Mine Damage-Advanced Trap Support (or Controlled Destruction)

At level 38 start using Cluster Traps Support on Arc:

4L: Arc-Trap & Mine Damage-Trap Support-Cluster Traps

Endgame Gems Setup

Shaper 5L (Trap Support): Arc-Trap & Mine Damage-Cluster Traps-Elemental Focus/Lightning Penetration (Pen will work better against bosses)

6L Spire: Lightning Spire-Added Lightning-Trap & Mine Damage-Controlled Destruction-Elemental Focus-Concentrated Effect (once again Lightning Pen can be used against tough bosses like Shaper)

Jewels are life, crit multi and lightning added damage:

 

Gear

For Leveling

Nothing crazy here. Double Lifesprigs, Wanderlust, Lochtonial Caress, Tabula Rasa

Get Axioms early on. It will help you stack crit fast. 

You can also use Fencoil which is a free Trap link, it can be later upgraded to a solid 6L!

At level 22 buy Deerstalker boots!

 

Shimmerons are absolutely BEST end-game DPS wand if you go the Power Charge route like me:

38% increased Spell Damage
39% increased Spell Damage
Adds 29 to 100 Lightning Damage to Spells
+10% to Critical Strike Multiplier per Power Charge
+0.3% Critical Strike Chance per Power Charge

+2% Chance to Block Spell Damage per Power Charge
Adds 3 to 9 Lightning Damage to Spells per Power Charge
400 Lightning Damage taken per second per Power Charge if
your Skills have dealt a Critical Strike Recently

The only thing that can get pretty close is some kind of a beast wand like this (also mine, but less DPS than Shimmeron): Glyph Charm Omen Wand

30% increased Spell Damage
27% increased Spell Damage
Adds 5 to 73 Lightning Damage to Spells
102% increased Critical Strike Chance for Spells

+38% to Global Critical Strike Multiplier
+20 to maximum Mana
+17% to Cold Resistance
36% increased Spell Damage

Or a good crit shield: Armageddon Pith Fossilised Spirit Shield

15% increased Spell Damage
+2 to Level of Socketed Fire Gems
65% increased Spell Damage
94% increased Critical Strike Chance for Spells

16 to maximum Energy Shield
+31 to maximum Life
+31% to Fire Resistance
+27% to Cold Resistance

The rest is pretty obvious:

Onslaught Shackle Stygian Vise

Has 1 Abyssal Socket
+253 to Armour
+97 to maximum Life
+40% to Fire Resistance
+37% to Lightning Resistance
+24% to Cold Resistance

Tinkerskin Sadist Garb

164% increased Evasion and Energy Shield
+88 to maximum Life
30% increased Cooldown Recovery Speed for throwing Traps
15% chance to gain a Frenzy Charge when your Trap is triggered by an Enemy
30% chance to gain Phasing for 4 seconds when your Trap is triggered by an Enemy
Recover 100 Life when your Trap is triggered by an Enemy
Recover 50 Energy Shield when your Trap is triggered by an Enemy

Gloves with +1 Trap can boost your damage by around 25%. But they will most likely drop your resists into abyss :D. If you can still balance your resists, use them for sure! It's a HUGE BOOST!

Domination Goad Arcanist Slippers

120% increased Critical Strike Chance if you haven't Crit Recently
+77 to maximum Life
13% increased Rarity of Items found
+39% to Fire Resistance
+43% to Cold Resistance
25% increased Movement Speed
+29% to Lightning Resistance

Gale Touch Hydrascale Gauntlets

Socketed Gems are Supported by Level 20 Trap
27% increased Trap Damage
Adds 4 to 10 Physical Damage to Attacks
+82 to maximum Life
+36% to Fire Resistance
+27% to Lightning Resistance

Dusk Claw Zealot Gloves

Socketed Gems are Supported by Level 20 Trap
+207 to Accuracy Rating
+22 to maximum Mana
18% chance to Avoid interruption from Stuns while Casting
Skills which Throw Traps throw up to 1 additional Trap
+57 to maximum Life

Inya's Epiphany Arcanist Slippers

120% increased Critical Strike Chance if you haven't Crit Recently
8% increased Intelligence
+70 to maximum Life
25% increased Movement Speed
5% increased Damage per Power Charge
25% chance that if you would gain Power Charges, you instead gain up to
your maximum number of Power Charges

These boots provide a smooth synergy between a counter productive charge generation of Chain Reaction (when you trigger all traps at once you don't gain as much power charges), so use them if you can balance your resists!

For the amulets and rings: high life, crit multi, spell damage, resists. Of cause Opal rings would be sick.

Any good Elder ring is a good pair with Shaper Ring:

Behemoth Charm Turquoise Amulet

+17 to Dexterity and Intelligence
26% increased Spell Damage
+13% to Global Critical Strike Multiplier
17% increased maximum Energy Shield
+45% to Cold Resistance
+38% to Lightning Resistance
+43 to maximum Life

Mark of the Shaper Opal Ring

25% increased Elemental Damage
20% chance to Trigger Level 20 Summon Volatile Anomaly on Kill
Adds 16 to 51 Lightning Damage to Spells
9% increased maximum Energy Shield
10% increased maximum Life
75% increased Spell Damage if your other Ring is an Elder Item
Cannot be Stunned by Spells if your other Ring is a Shaper Item

Jewels are life, crit multi and lightning added damage.

Flasks

1 Diamond for Crit
1 Atziri's Promise for Ele->Chaos DPS
1 Quicksilver
1 Basalt/Quartz
1 Eternal Life

you can have Sulphur instead of Basalt for more damage if you wish.

For HC you need more defense (evasion, armour, dodge flasks..)!