Rouji is generally quiet and often opts to communicate through his customized Haro rather than speak directly, especially in moments where he feels anxious. He is more comfortable speaking when discussing mechanical details, which he has extensive knowledge of despite being a first-year. He is also very observant, both of the mechanics involved in the duels but also of the broader events in the school and the world. He remains more awkward in social situations, most so when dealing with women that flirt or harass him.

As a member of the Dueling Committee, Rouji takes his commitment seriously and is dedicated to officiating and running the duels when he can. He works closely with Secelia Dote and is more comfortable with her, even if he does not always approve of the way she teases others.