User blog comment:Crimson and Darkness/Volume 24 discussion blog/@comment-185.112.105.215-20171117104644/@comment-31035098-20171117105835

The two new Super Devils was created by Hades. (As the spoiler said, one if them had potential to rival Dragon God) Other than that, theres also a 5 Maou class Devils and possibly a many Ultimate class Devils.

I think that's the reason why Ishibumi give Ise an upcoming AxA and ExE power up in the future volume.