User blog comment:B214/Volume 22 spoilers/@comment-66.50.41.60-20160926041302/@comment-9595671-20160926111130

Hmm... yeah, I guess when you consider he's able to gain strength in ways the past possessors haven't and how the whole Ddraig VS Albion fight seems to have been quelled into a friendly spar now, he's got that going for him.

Even if he doesn't solely rely on Ddraig's power, I think most sub-species balance breakers aren't that different from what Issei's achieved. It helps represent how many characters accept times are changing, Issie represents that well with his powers.