[Snake]

Twin Dance could be awesome on that, but also along with that, I'd wanna pitch in something for Archer too:

Freehand Barrage
Passive skill.
Main Class-only.

When using a Bow on your main hand, and a sub-weapon that is not a Bow (or no Sub-Weapons), your first attack done while under the effect of Longdraw will deal bonus damage equal to (Archer Class LV)% of your Scaled GUI, and if the attack is a Critical Hit, it will be repeated while losing 15% Hit and Critical per attack (max. 3 times).