From middle school onward, Ryoma was a talented tennis player with a bright future ahead of him, and had won championships around the world. But after he used his tennis skills and a custom-made steel tennis ball to kill members of an organized crime syndicate, he was arrested, found guilty, and sentenced to death.

Awaiting his punishment on death row before arriving at the Ultimate Academy, Ryoma claims he is no longer the same person who was bestowed the title of Ultimate Tennis Pro.

Displaying a maturity that is rare among teenagers, Ryoma seems older than his appearance would suggest. Even in the presence of pain and death, Ryoma remains unflappable.