Vulnerabilities: See Below
Resistances: See Below
Effective Garb: Cyber Jumpsuit / Quiet Guardian / Soldier of Peace / Dark Muse / Dragon's Blood
Ooh Caius--he's a tricky one. You need to pay close attention to the modes he uses. When he's in Ravager mode, throw fire, ice, lightning, and wind at him. When he switches to Commando, lambast him with your melee weapon.