Since Slash is low you can consider using either Corrosive or Viral. The [Gemini Cross] combo has some Slash forced Procs, so I went for Viral since it will really ramp up the bleed damage. Corrosive is better suited for those playing in the normal Star Chart instead of Steel Path. Also, the slide attack gimmick is best played with Naramon, as the combo builds up to 12x you will get orange crits all the time. If you don't have Naramon then for the combo duration you can use Dexterity Arcanes or exchange [Gladiator Might] with Drifiting Contact.

Enjoy :)