User blog comment:B214/Question and Answers 2/@comment-37.231.172.46-20140310210828/@comment-24098614-20140312200011

Vali is his strongest Rival that is true but he is not a enemy but a friendly Rival due to the fact that their relationship with each other has changed because Vali doesn't want to kill Issei because originally the rivalry between the two Heavenly Dragons was very fierce but now it has become a friendly rivalry between them.