Tomoru Aguri ・Toru's younger fraternal twin brother. ・He looks almost nothing like Toru. ・Has a calm and gentle personality. ・Speaks politely to everyone, but uses a slightly more casual tone with his brother. ・Doesn't like being treated as an invalid, so he prefers to do what he can by himself. ・Diagnosed with methylmalonic acidemia in early childhood. ・Still undergoes regular checkups and blood tests. ・Has a small appetite and eats in small portions. ・Needs to eat several times a day, so he brings supplemental snacks to school. ・His appetite itself is weak; he rarely feels the sensation of "eating because I'm hungry." ・Regarding food, it's not that he "hates" it, but rather that "having to eat is scary, troublesome, and exhausting." ・He must eat to stabilize his condition, but sometimes he cannot eat unless prompted by someone else. ・Often gags just by looking at food. ・Sometimes vomits if he forces himself to eat. ・Vomiting itself isn't rare for him, so he doesn't worry about it much. ・Vomits several times throughout the day on a regular basis. ・Has suffered repeated metabolic crises since childhood, resulting in motor impairment in his lower limbs. Walking becomes difficult when he is tired, so he uses a wheelchair when his condition is poor. ・Basically attends school in the infirmary, spending the day on an infirmary bed. ・Has poor eyesight due to his illness and wears glasses.

Toru Aguri ・Tomoru's older fraternal twin brother. ・Because their faces, physiques, and personalities are so different, people around them don't realize they are twins. ・Unlike Tomoru, he is healthy and belongs to the karate club. ・People are intimidated by him, but he's just blunt and clumsy at communicating. ・He becomes slightly more talkative in front of his younger brother, Tomoru. ・He is good at studying, but he isn't serious about everything; he sometimes skips class to stay in the infirmary to be near Tomoru. ・Since Tomoru often hides or downplays his poor physical condition, Toru has become skilled at seeing through it.