Komasan is a komainu, a traditional Japanese lion-dog guardian spirit. After centuries protecting a shrine until its demolition, he ventured into human settlements like Springdale, sparking intense curiosity about modern human life and technology.

Resembling a Shiba Inu, he has ivory fur with light blue accents on his stomach and ears. His long blue fiery eyebrows evoke hitodama flames, complemented by red swirls on his cheeks and hips. He carries belongings in a green furoshiki cloth and a green purse gifted by his younger brother Komajiro. By placing a leaf on his head, he transforms into a human teenage boy disguise.

Shy, gentle, and inquisitive, Komasan often exclaims "Oh my swirls!" in a country dialect reflecting his rural roots. Though occasionally timid, he remains fiercely loyal to friends and avoids confrontation. His fascination with human culture sometimes leads to unconventional choices.

During the dimensional event in "Sora Tobu Kujira to Double Sekai no Daibōken da Nyan!", Komasan witnesses Springdale shift from animated to live-action reality after a mystical whale emits a rainbow aura. He and Komajiro are eating ice cream when the transformation occurs, revealing his fondness for soft-serve. The dimensional chaos bewilders Komasan and fellow Yo-kai, while humans adapt effortlessly.

Komasan wields pyrokinetic abilities, summoning hitodama flames against foes though he seldom engages in combat. His Soultimate Move, "Spirit Dance," conjures will-o'-wisps to attack. He also possesses the "Alpha" skill, boosting spiritual power when paired with specific Yo-kai.

Across the franchise, he evolves into forms like Komane (via leveling or fusion) and Komasan S. He is pivotal in unlocking other Yo-kai such as Komashura and Spoilerina under certain gameplay conditions. His human disguise features prominently in anime segments like "Komasan In Love," navigating human social dynamics.