User blog comment:Crimson and Darkness/Volume 25 discussion blog/@comment-2602:306:CD9A:C860:D9E5:F379:39CA:57B5-20180603215326/@comment-217.136.96.176-20180608094950

Well, the promotion to an evil piece would increase an individual's trait: Speed for Knight, Strength and Durability for Rook, Demonic Power for Bishop. The Queen Piece would increase all these traits to a greater amount. However, the evil pieces are not almighty. So if the user is already strong, the added amount is not much. It's what I believe. If not, they would be ranked as King Pieces.