User blog comment:Crimson and Darkness/Shin DxD 3 discussion/@comment-43933896-20191007165916/@comment-77.192.107.58-20191007195615

It would be logical that Issei becomes Ultimate-class devil because since he has become a high-class devil, he beat Vidar, Nyx, Erebus and Tartarus, ajuka said that in devil history, it never happened that a devil beat as many opponent of this caliber.