Arcane Gear Setup and Skill Priority

Intellect DPS Arcane uses Hot Work Gear Pack 3-piece as the core set, while Will support Arcane targets 640 Will with Eternal Xiranite Gear Pack.
Intellect vs Will Build Direction
Arcane splits into two skill branches depending on which stat is higher.
Higher Intellect favors personal damage and Corrosion. Battle Skill and Ultimate do most of the work, and Finishers inside Ultimate can force Corrosion.
Higher Will favors grouping, extra Infliction, and Susceptibility. Combo Skill is the anchor, and Will raises susceptibility scaling.
Pick Intellect when the team needs damage. Pick Will when you already have a main carry like Yvonne or Last Rite.
Gear Setup (Intellect DPS)

Hot Work Gear Pack
Engineering Division

Hot Work Gear Pack
Engineering Division
Intellect DPS gear pack with red EXO-1 plating from Engineering Division.
Intellect Arcane usually runs Hot Work Gear Pack 3-piece. The last slot can be another high-Intellect kit or a second Hot Work Gear Pack piece.
Hot Work Gear Pack pairs well with Corrosion from Ultimate because of Arts Intensity and Nature damage bonuses. A signature weapon with ultimate charge speed helps Ultimates come back sooner.
If Ultimate feels slow, add gear with ultimate charge options.
Gear Setup (Will Support)

Eternal Xiranite Gear Pack
Hongshan Swordmancers

Eternal Xiranite Gear Pack
Hongshan Swordmancers
Will support gear pack with black tactical armor and mint-green accents from Hongshan Swordmancers.
Will Arcane often uses Eternal Xiranite Gear Pack 3-piece. Stack Will on armor, gloves, and kits first.
Combo and Ultimate grant team damage bonuses, and higher Will improves Susceptibility. At max Combo level, around 640 total Will is needed for full susceptibility scaling.
Match weapon ultimate charge with how often you want to use Combo.
Weapons
Signature Type 42: Solemn Phalanx gives Intellect and ultimate charge speed. Passives change depending on whether Intellect or Will is higher.
Without signature weapon, Battle Pass Junction Point is the usual substitute. Will-focused alternatives also work for support builds.
Skill Priority
Combo Skill > Battle Skill > Ultimate > Basic Attack
Combo Skill cooldown drops as it levels, and Will builds also tie max Susceptibility to Combo level. Level Combo to mastery first.
Next put points into Ultimate and Battle Skill. Intellect builds lean on those for damage; Will builds chain Combo into Ultimate and Battle for grouping and Infliction.
Basic Attack only matters for Finisher timing. Leave skill points for it last.