User blog comment:Alcahona1095/High School DxD BorN Episode 11 Review/@comment-5586509-20150614015211/@comment-26476349-20150614025924

Loki is to blame. He wishes to bring about the end of the world with Ragnerok. He cursed them. Rias did become attached to Issei and jealous about his relationship with the others. Issei himself can be blamed for his fear of a serious relationship. Like with Yuma when she killed him on their first date. Loki exploited this fear and turned Rias against Issei and the rest of her family. So you can't only blame Rias for these incidents. But yeah if she did not care for them they would all be dead.