Riku’s early years were marked by a great deal of suffering and tragedy. After his father passed away, a Yakuza boxer taught him how to throw a punch, and when he had to defend himself against his mom’s drug dealer, that punch saved his life. He ultimately killed the drug dealer, establishing himself as a murderer. Criminals kept chasing him, causing additional sorrow for those who tried to take care of him. All of this prompted him to approach the same former boxer to help him develop his strength, which brought him to a dilapidated gym and opened the door to the professional boxing world.