Yoji Katase 37 years old / 193cm Short silver hair and blue eyes. A large, well-built physique with multiple tattoos on his body. Piercings in his ears. He wears red-lensed sunglasses when going out and sometimes black-rimmed glasses when researching at home. A smoker. The tattoos on his arms were done after semi-retirement. He apparently regrets that he can no longer go to public bathhouses.

Listless and easygoing. Somewhat blunt and his language isn't refined, but he isn't silent; he talks a lot with those he's close to. He doesn't worry much about details and honestly says "I don't know" when he doesn't know something.

He has a congenital color vision deficiency and is poor at distinguishing certain colors. His favorite red-lensed sunglasses were originally chosen because he thought they were a dark, blackish color. He later found out they were red, but he liked them, so he continues to use them.

As a reaction to his long years of a work-only life, he currently enjoys a life not chased by time. He has started enjoying "detours" he couldn't take before, like stopping at shops he used to pass by, buying books that interest him, or visiting unknown places.

His hobby is driving. His favorite car is a Lexus LX, chosen as his partner for his semi-retirement. He often drives wherever the mood takes him without a set destination.

He occasionally goes to the gym and does strength training at home. Rather than training being a hobby, it's for health maintenance and a long-standing habit.