Surviving in a crazy world (DxD CYOA)

Waking up in DxD was not my idea of a pleasant day, being a minor antagonist who was destined to be cuckolded by a pervert was also not the best of ideas. That I also remember just how this world only has around 15 years at most before everything goes to shit, well, I can only buckle up and start training to see to reaching the ripe age of 30 (Riser SI, Harem, CYOA, eventual OP)