User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-75.71.34.254-20150326233658/@comment-1359322-20150327021747

Yeah i'm guessing that it's a King Piece which serves as the origin to all Evil Piece, meaning it's not the King Piece that is placed into a body of a Devil but a King Piece that is use to create other EP. Sorry for not making my point clear.