[ A difference in how the two personalities handled things, something that all four of them share. Then, he's all the more willing to volunteer and help Allelujah use them best. ]

Likewise on my end. I have better control over familiars and flags, while Berserker... fights better in general. His siphon ability is superior.

[ So they could theoretically work well if they know how to switch and coordinate. Henry is willing, but Edward less so. ]

We can practice with our current selves, then? It will be less risky that way.