User blog comment:B214/Talk About What You Want! 3/@comment-75.64.241.32-20150201052145/@comment-1359322-20150202110309

@anon, that's wrong, the Evil Pieces are base on compatibility. Knight is speed, Bishop is magic, Rook is power.

@Gary, i don't think that statement is accurate, Mutation Piece aren't really a symbol of strength but more like a symbol of potential. Look at Ise, he was reincarnated using 8 Pawn Pieces, something probably accomplish-able by a Mutation Piece. But that doesn't represent Issei's strength, it just shows how much potential Ise has. Even Gasper was weak initially despite being reincarnated using a Mutation Piece.