Sorry for posting one, but I said it wrong at the end of the chapter. I want to make Blaise a Rook, and Rossweisse worth a Pawn. Reason being I'm don't want to bother with promotion (call me lazy.) And the other is well… I'm notorious of not finding common information.
Such as Mutation Pieces. IF I'm not mistaken Rias used all her mutation pieces on Gasper and Issei.
I have no fucking clue how those works :(