User blog comment:B214/Volume 22 spoilers/@comment-187.195.211.194-20160726161803/@comment-9595671-20160727054445

In some fanfics I've read, I've seen cases like this tournament where someone is temporarily part of a peerage in a Rating Game. So I think I know a way they can promote or have the benefits of each piece type.

Perhaps those who are part of the groups for the tournament are given something that replicates the traits of an Evil Piece, or maybe the field for the game itself is made to temporarily give them those abilities during the match.

It wouldn't surprise me if Ajuka managed to create something like that just for this tournament. Also this still works in balancing out those who are gods because Evil Pieces and Brave Saints can't be used on them.