[EnerPrime]

Honestly, I'm not all that impressed with the whole 'some Invess used to be human' thing as a twist. I know Sid saying that killing InvessHase was a heroic thing is supposed to be a big shock, but he's not exactly wrong. Hase was going around hurting and potentially killing people, and there's no real evidence to suggest he could have been saved. Even when he partially turned back, he still just acted like an Invess that looked human.

It just strikes me as being an obvious twist that doesn't really add anything new to the story but angst potential.