User blog comment:DeathGodPrayer/Talk About What You Want!/@comment-4547267-20140119030701/@comment-1359322-20140119032655

I think that one would go to Sirzechs and Grayfia. Rias and Issei's relationship are supported by many people after all. Plus Issei would have married quite a number of girls by then. Issei's daughter might view her uncle and aunty's love relationship as purer than her parents' one.