Atsumu “Yukiatsu” Matsuyuki is a tall, handsome young man with a slim build. His light brown hair is cut short, with bangs parted on either side, framing his face, and his striking green eyes add to his intense and often brooding appearance.

He typically wears his school uniform, which consists of a white collared shirt with a left breast pocket, adorned with an emblem. His shirt is neatly tucked into dark blue jeans, secured with a brown leather belt with a silver buckle. A burgundy tie complements the look, and he wears brown shoes. Yukiatsu also sports a wristwatch with a brown leather strap, completing his put-together and polished appearance.

As a child, Yukiatsu’s outfit was more playful and casual. He wore a blue and yellow cap, which featured a fish inside a circular emblem, and a white, collared, button-neck shirt. His attire was complemented by very short denim shorts, white mid-calf socks, and orange-and-white running shoes. This look reflects his carefree, youthful personality during his early years.

Atsumu “Yukiatsu” Matsuyuki has a complex personality shaped by unresolved grief, unrequited love, and a lingering sense of guilt. In the present, Atsumu exhibits a condescending and antagonistic attitude toward Jinta “Jintan” Yadomi, masking his own pain and frustration over Meiko “Menma” Honma’s death. He becomes visibly agitated whenever Menma is mentioned, struggling to suppress the deep emotional scars her loss left behind.

Atsumu remains trapped by his memories of Menma, harboring unresolved feelings for her. He keeps a white sundress similar to hers in his closet and, at his lowest moments, dresses in the outfit paired with a wig, wandering the forest at night. Atsumu even claimed to see Menma’s ghost and spoke on her behalf, though it was later revealed to be an illusion of his own making. His crossdressing behavior stems from his guilt over confessing his feelings to Menma on the day of her accident, believing himself responsible for her death. He feels that he, not Jintan, should be haunted by Menma’s spirit. Though he stops crossdressing after being caught, Atsumu remains haunted by the idea that Menma’s ghost only appears to Jintan and not him.

Despite his condescending demeanor, Atsumu occasionally reveals his vulnerability. He confides in Naruko “Anaru” Anjou, acknowledging how both of them are left behind by their unrequited love for Jinta and Menma, respectively. This shared pain leads him to label them as “kindred spirits,” though his manipulative tendencies sometimes surface in these interactions.

Atsumu’s dark and manipulative side is fueled by his lingering affection for Menma and his childhood inferiority complex. Despite this, he is a hardworking and exceptionally intelligent individual, consistently excelling in academics and ranking second in his class. Menma herself recognized these traits in a letter to him, stating,“I love how hardworking and strong you are.”