User blog comment:B214/Volume 22 spoilers/@comment-173.185.123.104-20160909174547/@comment-10330822-20160910113055

I think her being Tiamat would be dope. My only conern is the mention of her being a devil, and as far as we know only Tannin is a devil. Still, if it is her, than it would mean Issei has both a Dragon King and a former Dragon King's son on his team, that's a pretty stacked team.