Yoshioka was a former singer in a band. During the events before the start of the death game, Yoshioka along with his band members, raped Miho, Arisa and Yuki along with himself attempting to rape Himiko. Which made Yoshioka and his band indirectly responsible for Himiko's firends nominating Himiko into the death game. Later in the story it is revealed that Yoshioka was also sent to the island to compete in the death game, being one of the 32 competitors.