User blog comment:B214/Question & Answers 5/@comment-82.199.205.219-20151128164857/@comment-73.139.252.52-20151128220713

In part one, it is observed by Azazel that Kurenai and Zen have dragon wings. Its safe to say Issei's other kids may also have dragon wings. Also all his kids are insanely strong so they have inheirted that from their dad as well as their moms