User blog comment:B214/Volume 23 discussion blog/@comment-177.177.104.45-20170618154943/@comment-31137559-20170618222147

I never remembered Issei being battle crazed. I think you mean being a straightforward power idiot who fights with her fists. That's what Airi got from Issei. Issei's a pervert and he didn't get that from his parents. Zen is a swordsman who focuses on technique, yet his parents are power idiots.