The Testament of the Rosario DxD: Issei hyoudou the Makai Knight(Small Haitius)
After issei had defeated Riser Phoenix in the battle for Rias gremorys hand in marriage, he was betrayed by Y/n Hater and Sirzechs, not only forcing Rias to marry Y/n Hater, but also taking his sacred gear, the boosted gear, and leaving him to die. Luckily for him, Ddraig sealed a portion of her life force inside him...