Rouji is a first year student at Asticassia School of Technology, in the Mechanics department. He is a member of the Dueling Committee, a student body responsible for overseeing duels at Asticassia and a student council of sorts, and is very knowledgeable about mobile suits and other mechanical craft. 

He is a very shy and introverted boy, who prefers to let his personally customised Haro unit speak for him. Nevertheless, he is able to keep calm under stressful conditions.