User blog comment:B214/Volume 22 spoilers/@comment-50.139.232.230-20160923232938/@comment-9595671-20160924055740

I think that's why Zekram said that when he had a chance to... but I think the King Piece's reveal, which I think has been implied to be something Zekram actually knew of possibly, might tell Issei "I should not trust this guy"