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

People seem to forget the ExE world has 2 factions, one of which opposes the bad one and can still remain despite at war for an "unknown period of time". As such, the bad faction cannot send all of their forces that easily to conquer another world. Another reason why they study the DxD world is to strengthen their subordinate, increasing their force against the "good faction". In truth, invading another world when you are already at wat is a stupid move, except if that world is weak compored to them and can help them strengthen themselves. Inversely, it is also possible that the good side, including Chichigami will be more active to help the DxD world. Yeap, Issei will once again have new power-up (it really becomes absurb, as he could, I don't know, just multiply his power more and more. A superior form would be more useful to Vali which needs to close down the gap with his opponent to divide and absorb their power).