User blog comment:Crimson and Darkness/Shin DxD 4 discussion/@comment-40183495-20200221101007/@comment-37560916-20200221122125

Dude, the new power up for Issei wasn't absurd. He trained a lot all this time, this is stated several times in the novel(Specially in the Tournament Arc), also, with his emotions,  he was capable of active this new form; remember that Sacred Gear work trough emotions and feelings. Also, remeber that Vali is just as strong as Issei(I'm not talking about "strength" itself, I'm talking about combat), even with the AxA, Issei can be defeated by Vali, Ddraig said this in Shin DxD 3. Anyway, I also would like to see a power up for Vali, and I think Ishibumi will do it in the next Volumes.