Overview
This Gemling Legionnaire plays as a mobile lightning caster that barely casts its damage by hand. A Cast on Critical setup fires Arc and Ball Lightning automatically, while Lightning Warp moves the character between packs. Arc chains through groups for clear, and Ball Lightning keeps steady pressure on tougher targets.
Damage scales through Archmage, so maximum mana, mana sustain and spell damage all push the trigger spells harder. Gemling Legionnaire adds the extra gem slots and a defensive layer through Virtuous Barrier, which suits a build with many linked supports.
The creator scores it 3/5 for league start, 4/5 for bossing, and 5/5 for mapping and scaling. It is at its best on a geared character that keeps moving and lets the triggers do the work.
Pros & Cons
Pros
- Arc and Ball Lightning fire on their own, so damage keeps flowing while the character moves
- Very fast mapping from Arc chains plus Lightning Warp mobility
- Archmage scaling means every mana upgrade becomes a damage upgrade
- Lightning Warp doubles as a dodge for boss mechanics
Cons
- Needs consistent crit chance so Cast on Critical triggers smoothly
- Mana sustain must be fixed early because the build depends on spell uptime
- Weak in the early game before the trigger engine and Archmage come online
Key Skills
- Cast on Critical (Arc + Ball Lightning): the main automatic damage package
- Lightning Warp: mobility and repositioning, linked with Rakiata’s Flow
- Archmage: mana-to-damage scaling with Lightning Mastery
- Arctic Armour: defensive buff supporting the elemental setup
- Explosive Transmutation: extra spell interaction, run with Arbiter’s Ignition and Spell Cascade
Gear & Anointments
Stat priorities are spell and lightning damage, critical strike chance and damage, maximum mana, mana sustain, cast speed, cooldown recovery and defences. Siphon Elements, Mana Remnants and Charge Regulation round out sustain and charge uptime. The video does not name specific uniques or an anoint; check the creator’s linked build for the exact items.
Endgame Notes
For bosses, keep the triggers running, use Lightning Warp to step out of mechanics, and never get locked in one spot. Rares and elites go down as Arc and Ball Lightning stack pressure while Archmage boosts every hit.
Credits & Source
Build credited to RNGenius. See the source video for the full gameplay footage and commentary: CAST ON CRITICAL ARC GEMLING LEGIONNAIRE BUILD GUIDE | PATH OF EXILE 2 PATCH 0.5.5.