User blog comment:FrankieX98/The future members of the Issei's harem and peerage./@comment-2601:87:8300:20D0:5543:CD45:A7F7:DF0D-20181027144124/@comment-108.7.145.117-20181027154356

Why wouldn't Kunou be part of the peerage? Because she's a Yokai princess and to reincarnate her as a devil will be like renicarnating Irina as a devil. However she's definitely going to be part of the Harem, maybe in her arc they'll unlock her latent abilities to become a Kyuubi like her mother.

However theoretically for a reincarnation I would agree with the idea that she'd be worth a Rook.