Josuke is the fusion between Yoshikage Kira and Josefumi Kujo. Kira was a marine surgeon whose mother Holy fell ill from the Rock Disease, a curse plaguing the existence of the Kira and the Higashikata bloodline. Kira learned of the existence of the Rokakaka Smuggling Organization by accident, and the existence of the Rokakaka, a miraculous fruit which could heal any ailment at the cost of another body part.