Saitō is a man with white hair. He originally had brown hair that was believed to have turned white after being traumatized over seeing Muranushi's smile, though he claims he just likes dying his hair. While on duty, he wears a white shirt, black necktie, black suit and black pants.
Saitō is dedicated with his work as a bodyguard but known to run off if frustrated.
- Tasaka: Saitō admires him as his senior.
- Shiho Kamakura: Despite being his employer, Saitō has little respect over her.
- Sayuri Muranushi: They are childhood friends along with Kisaki Kondou. It is revealed that he developed a crush on Muranishi and because of that, he used to bully Muranushi. Saitou however did not deny this fact when Shiho actually joke with him about this. Somehow, he sensed that Adachi 'suffers' the same symptom as him on their first meet.
- Masahiro Adachi: The first time he met Adachi, he sensed that Adachi had the same sort of aura as himself. This is due to both have witnessed Muranushi's smile.
- Despite being Shiho's bodyguard, his actual task was to protect Yuuta from being physically harmed by Shiho