Green Butcher of Four Kingdoms

Y/N "Cioccolata" L/N is a former doctor that lost his position due to the deaths of several of his patiens. However, those deaths weren't accidents, as other people thought. Instead, it were deliberate murders. Wandering over Clover Kingdom, Y/N, at some point received thing called Stand - a physical manifestation of his life energy - and called it Green Day. Using his newfound powers to slaugther people at his heart's demand, he was found by Dark Triad during one of his killing sprees and received an offer to join them. Y/N happily agreed to do it, unaware how his life will change after that.