User blog comment:Mnzombie/Issei's Peerage/@comment-139.168.116.203-20131206051903/@comment-16281343-20131206113548

IMO, the Evil Pieces that are given to a Devil does not include a King piece, so the King does not have an Evil Piece inside him and can still be a subject for "reincarnation".

Hmm, maybe Ravel is already qualified to have the Evil Pieces but does not have interest yet? Because in Rias' case, she is already fixated on the dream of becoming the Rating Game champion even before she got hers (Am not sure if that is only my opinion or it is stated in the novel, so can anyone please confirm it :D).