User blog comment:AhmaddamhA/Change in Issei's Evil Pieces./@comment-1359322-20160701020804

Ajuka never said his Evil Pieces change into attributes of other Pieces, he merely said it evolved into Mutation Pieces presumably due to the effects of Triana and CCQ. So Ise's Pawn Pieces are still Pawn Pieces, it hasn't become other Pieces. And it can't become a King Piece either.