User blog comment:Crimson and Darkness/Shin DxD 3 discussion/@comment-41.13.5.248-20190820095832

So AXA is a combo technique he does with ruytemaru and not really a power up. Which means that until he changes into a great red dragon and becomes the True Oppai Dragon he won't get any other power up. Ingvild is the only hope Issei has to become stronger.