User blog comment:B214/Volume 22 spoilers/@comment-112.198.82.246-20170217114129/@comment-31137559-20170217141627

They are considered equals. I know Issei's body was created from Great Red's flesh and Ophis' power, but it didn't just automatically make him more powerful than anyone else, especially Vali. His new body put him on an even playing field with Vali. Vali had his immense demonic powers which allowed him to survive the curse from the strongest dragon slayer. And look at what Sirzechs did with his demonic powers and the Power of Destruction. What do you think that battle maniac can do with his demonic powers?