I'm Vengeance (Male Reader X Highschool DxD)

Out on patrol, Y/n and his brothers interrupt an arms deal with some of Gotham's villains. After their mission, they find out that the Joker is running around Gotham terrorizing it's people. Wanting to put a stop to it, Batman refuses to let Y/n go and makes his stay at home. Going against his wishes, he goes anyway and that leads to Batman's demise. Wanting vengeance for Bruce, Y/n follows Joker to Japan to put in end to him. Will Y/n enact his revenge? Will Y/n break the code to never kill? What other villains make their way to Japan? Will Y/n finds new people to call his Allies or enemies?