Zero isn't having an easy time of it when the fight starts. Weil turns translucent and invulnerable, copies himself, uses something that looks like an electrical attack - though it might be noted that it's purple, heals himself, has a couple different homing attacks... one of which can't be destroyed, and is generally an extreme pain in the ass. "I don't care what he's done to himself, no human should be this hard to kill."