Kairo Sakashi a demon from another world who contains the soul of Barbatos, his world fell into ruin because of the war between the Demons of Hell who want to wipe out humanity to conquer Earth and the Angels of Heaven who protect humanity, but after seeing the reason why the Angels protect the humans he switched to the Angels side to kill his own kind, but in the final battle against the Demon king Bael he sacrificed himself, but he wakes up in a new world where all the supernatural exists , where then he becomes the second pawn of Rias Gremory, so let's see how the devils and other supernatural beings react to a demon in the world. Did I forget to mention he is the adopted son of the Hyoudou family. Disclaimer: I do not own Highschool DxD or Gundam, just the story idea and my Oc