User blog comment:B214/Volume 23 discussion blog/@comment-95.90.224.203-20170415081527/@comment-10330822-20170417030704

Because these just aren't any dragon's body, its Great Red's. That is why I worry, Issei is essentially using a combination of the powers of the greatest beings in the existence.

Also, the comparison with Sairaorg isn't quite accurate, because, to be fair, Rias's Power of Destruction isn't already stated to be on multiple verges of evolution. For all we know, she isn't getting much stronger than she is now. Issei on the other hand, is undoubtably is.

Also, Sirzechs and Ajuka aren't really much in comparison to beings like Great Red and Ophis. That is why I worry. Vali can become every bit as strong as Sirzechs and Ajuka, but the question is, will that match whatever is happening to Issei?

That is why I would feel more comfortable with him getting something from Trihexa, because let's face it, Lucifer isn't much of a milestone here in terms of power.