He is a crybaby and it makes one wonder why he became a guard in the first place. He tends to be the victim of bullying by the inmates and whenever a stressful situation occurs, he breaks down and panics. He looks up to Hajime as an older brother/mentor figure, who tells him he needs to step up and become more confident because if he manages to survive in Nanba prison, he can survive anywhere. Part of the reason he is bullied is because he is a crybaby whose authority they don't respect and because he is a pretty boy. However, when they don't bully him they usually have him act as a servant, getting him to deliver them stuff they want so they won't be motivated to leave their cell. Seitarou himself doesn't realize this, but is happy when they don't bully/tease him and stay in their cell, stating he is developing a better relationship with them. This implies that despite his fear he does try to act nicely with them. Despite this, he is a hard worker and does his best at his job. When not crying he is a polite, calm person who does his duties. He is fairly formal and despite being afraid of the inmates, does try to act kindly to them. He is a shy and reserved person who is rather soft-spoken, becoming nervous even around the other guards. He is also very modest. He has an extremely good memory and also seems to be intelligent and patient, often explaining to the Cell 13 inmates the events happening at the prison.