User blog comment:B214/Volume 22 spoilers/@comment-154.242.38.77-20160819230516/@comment-95.90.227.125-20160820121933

I don`t think Issei Pseudo Form is much weaker than Vali`s. Would dare to say they are equal. And unlike Vali`s Issei`s From will grow and get stronger  with him. But yeah I think it is Time where Issei should grow much Stronger than his Rival. Even if he becomes a Main Support Character, he is in the End the Rival for the Main Character (Issei). And the Rivals most important Existence is so that the Main Character will grow much stronger, that is Fact. So Issei train and become a Being of Shiva`s Class.