Red Dragon's Journey in a new world.

Issei Hyoudou, a boy too familiar with betrayal and deception, had his final straw of betrayal when his own brother who had mistreated him stabbed him in the back. Dai had killed him with after the Factions were swayed by his lies, his brother no longer proved useful to Dai

However, that was not the end of the story, he was sent to a different world. He along with Ddraig were sent to a different world. Where they were given a chance for a new life, he and Ddraig eventually decided to settle down and live their lives properly.

But what would happen, if the Faction Leaders want him back?

High School Dxd belongs to Ichiei Ishibumi
Massive thanks to @TimmyShadowKing for letting me use the idea of Isekai