User blog comment:HollowIchigo58/High School DxD Season 4 Announced/@comment-30329599-20161027160552

Aito Ohashi who did some of the Key Animation of Season 1 and 2 needs to do more then just OP key frame work, its why the 3rd season had poorer animation quality overall. He needs to be the Main Animator of Issei vs. Sairaog Bael