|Occupation||Former Singer and Guitarist|
|Japanese VA||Yousuke Iwazaki|
|English VA||Johnny Delacerda|
Yoshioka is a tall young man with an average build. He has rose wood-colored hair and brown eyes. His attire consists of a black button-up shirt, black pants, and a St. James cross necklace.
In the present, he now wears a hoodie jacket and carries a machine gun out of nowhere.
Yoshioka is a heartless man, one who was unhesitant in exploiting women for his own benefit, as he will take everything he wants and killing everyone who dares to get in his way, even if some of them are kids like Kosuke Kira and Kaguya.
In high school, Yoshioka befriended Himiko. Some time after his band Judgment Flash gained popularity, he invited Himiko and her friends Miho, Arisa, and Yuki to meet him and his band members at his apartment. While Himiko was retrieving snacks for them, Yoshioka and his band members drugged the three others and raped them on film. When Himiko returned, shocked at the whole incident, Yoshioka attempted to drug her. However, Himiko punched him and fled. Yoshioka, along with his band members, were later convicted for their crimes. However, these crimes would later indirectly cause Himiko's nomination for the real-life Btooom! game. 
Yoshioka is also nominated for the real-life Btooom! game in the present. Before re-encountering Himiko while she was still injured in the said island, Yoshioka somehow got a machine gun out of nowhere. 
Once Matthew Percier's crew arrived to get Ryouta and the other surviving Btoom! players to escape while giving time to get Yoshioka and Himiko as well, Ryouta tells Yoshioka to surrender himself to get out of the island quickly. Unfortunately, Yoshioka refused, and hopeless for his own good, he instead attempted to kill Ryouta and the other Btooom! survivors. As Himiko fights back and pushes Yoshioka from the stairs of the abandoned factory, Yoshioka falls to a river nearby the factory behind, and is finally killed in the river by Ryouta for good which ends Himiko's nightmare. 
Equipments and skills
- Machine Gun