A childhood friend of Menma and Jintan and he has affection towards Menma. He cannot forget Menma, even after her death.
In the present, Atsumu holds a condescending and hateful attitude towards Jinta. He becomes agitated whenever Meiko is mentioned and tries to hide that he is still distraught over her death. He and Chiriko attend the same elite high school, which Jinta was unable to enter due to failing the entrance exams. Atsumu is handsome, athletic, and popular, but still trapped by the memory of Meiko, keeping a white sundress similar to hers in his closet. He claimed that he could also see Meiko's spirit, and even spoke on her behalf, but this 'ghost' turned out to be Atsumu himself, who would wander the forests at night dressed in a wig and the white sundress. He took blame for Meiko's death, as he'd confessed feelings to her on the day of her accident, and says that he is the one that should be haunted by Meiko's ghost because of this. Although he stops crossdressing after he is caught, he is still tormented by the idea of Meiko's spirit appearing only to Jinta. Atsumu confides in Naruko on how they are both left behind by their unrequited feelings for Jinta and Meiko, saying that they are kindred spirits. Atsumu has a dark, manipulative side driven by both his affection for Meiko and his inferiority complex from childhood.