Rise of The Moon Deity (Kokushibo Tsugikuni X MHA)

After defeating his brother, Michikatsu AKA Kokushibo had an epiphany, his brother was still far stronger than him despite all of the training he did, he would never win... at this pace. instead of reporting to his master, Kokushibo would begin to do the unthinkable, he would lead a double life, on one side he would be the second most powerful demon, and on the other he would be a man giving the slayers information from the shadows. however neither of these lives were his true intentions or goal, instead his true goal all along with something much bigger than any could have imagined