User blog comment:B214/Volume 23 discussion blog/@comment-172.56.17.58-20170417051436/@comment-1359322-20170419134658

Why am i having so much trouble with you people? @Pawn,

"Pure-blood Devils, in other words Buchou and Raiser. A pure Devil. It means their parents are also pure-blood Devils. A real Devil. Asia and I will be categorised as reincarnated Devils then."

- Volume 2

Does Ise fits this requirement? No, he doesn't so Ex is not a Pure-blooded Devil.