Hisao is a male high school student with arrhythmia. In the prologue he collapses from a heart attack after receiving a confession from the girl he likes. He is detained for several months in a hospital, during which they break off relations.
Due to his condition, Hisao cannot return to a normal high school. Instead he is transfered to Yamaku High School, a school for the disabled.
Hisao's main hobby is reading, which was his sole escape from the boredom of staying in the hospital. Before his heart attack, he also used to play soccer casually with friends.
Hisao has brown eyes and messybrown hair with an ahoge. He usually wears the Yamaku high school uniform; when in casual clothes he is usually wearing a distinctive-looking sweater vest with a grey checkerboard pattern. His chest has a scar from heart surgery, though how noticeable it is varies by artist.
