User blog comment:B214/Volume 23 discussion blog/@comment-185.112.105.215-20170514051136/@comment-29963364-20170514051502

It's basically what Kunou calls Issei's Harem.

All of the girls are constantly "battling" for Issei's affection. And when a fight between the girls breaks out (usually between Rias and Akeno), it's like a scene "from Hell."