Highschool DxD FanFic - The Heavenly Brothers
Gasper got taken away by the Khaos Brigade and was used to stop time. While they were going to use him again they triggered something in him and reverted time. It didn't took much time for Issei and Vali, the Heavenly Brothers, to realize what happened and when they did they were mad. I mean like really really mad. All those memories are now lost so they are going to bring them back, no matter what.
This is my first only-highschool-dxd fanfic so I hope you like it!