Kiyoshi is a tall and handsome young man of average weight with dark blue hair, black eyes and he is lean at the start of the series, but he gains some muscle during his incarceration in the Prison Block of the school.
During his stay in the Prison Block, Kiyoshi wears the standard male prison uniform of a sleeved white striped shirt and striped trousers.
Kiyoshi is a level-headed individual who seems to have a strong resolve under hard pressure. Unlike the other boys, he does not let his desires get ahead of him, and tends to be the rational member of the group. Kiyoshi is markedly the most normal of the boys in design and character, as well as the main narrator of the manga in thought.
He is tenacious but lacks the stubborn perversion of the other boys. However, he is capable of sometimes doing things that seem untoward or shocking to the other boys, such as cross-dressing to escape the Prison Block. Kiyoshi can be oblivious to his selfishness sometimes as seen when he intended to use the money that he gathered from other to buy something for his own personal reason. Kiyoshi can also be insecure with the other students and can be driven to action by other people's resolve.
(Source: Prison School Wiki)
