Ashiya Ashibe is a cheerful and optimistic six-year-old boy with black hair styled symmetrically on his head featuring a distinct thin strand, black vertically elongated eyes, and thin curved eyebrows. He typically wears a yellow T-shirt, light blue shorts, and white socks. After moving, he discovers a white creature he initially mistakes for a large fish; it is revealed to be a baby spotted seal. Though disappointed it isn't edible, he grows affectionate upon its awakening, names it Goma-chan, and adopts it as a pet. His caring nature leads him to disguise Goma-chan from his mother and enthusiastically introduce the seal to classmates on his first day of school.

He quickly befriends classmates like Yuma and Mao. When facing bullies such as Sakata and his older brother, Ashibe bravely reassures his friends and uses a non-violent pacification technique called the "Brotherly Love Hold," taught by his friend Sugao from his previous town; this hold subdues aggressors by evoking feelings of happiness. Ashibe frequently makes peace hand signs while exclaiming "Peace!" when meeting others or expressing cheerfulness, a behavior more prominent in the anime than the manga.

The original manga serialized from 1988 to 1994 depicts his young childhood with Goma-chan. The sequel manga "ComaGoma" (2000–2004) shows him as a second-grade student. Another sequel, "Shō 3 Ashibe QQ Goma-chan" (2020–present), follows him in the third grade. "Seishōnen Ashibe" (2017–2024) portrays him as a high school freshman. The anime "Shōnen Ashibe Go! Go! Goma-chan" (2016–2019) focuses on his first-grade experiences with Goma-chan, family, and neighbors.