Komajiro is a komainu yo-kai resembling a shiba inu, clad in ochre fur with cream patches accenting his muzzle and stomach. Darker ochre shades his inner ears and tail, while light blue eyes peer out beneath distinctive long, brown, flame-like eyebrows. Brown swirls mark his cheeks and hips, and he carries a blue pouch decorated with a swirl pattern.

As the younger twin brother of Komasan from the Charming tribe, Komajiro shares his sibling's innate curiosity and optimism but adapts far more readily to urban life. He quickly masters city lingo, technology, and even works as a nightclub DJ under the alias "KJ." This adaptability sometimes sparks jealousy in Komasan, though Komajiro consistently views his older brother as an inspiration and strives to support him. His primary yo-kai ability causes humans to struggle to locate items they seek. In video games, he wields electricity-based powers, unleashing lightning bolts and a "Wild Zaps" Soultimate Move, abilities not present in anime or manga portrayals.

Komajiro and Komasan share a close bond, living together and frequently embarking on adventures marked by mutual admiration. Komajiro occasionally expresses higher expectations for Komasan's adaptability. Their family background expands in the film *Yo-kai Watch: Enma Daiō to Itsutsu no Monogatari da Nyan!*, where a visit to their mother in the spirit realm reveals a new human baby sibling, Komasaburō, highlighting their mother's unexpected cross-species caretaking. This storyline underscores Komajiro's connection to his rural origins and family ties.

Across the franchise, Komajiro appears in multiple media: he evolves into Komiger at level 33–35 or through fusion with a Swirly Soul in the core video games. He is playable in titles like *Yo-kai Watch Blasters* and *Yo-kai Watch: Wibble Wobble*. His anime debut occurs in Episode 9, with recurring roles in mini-segments and the aforementioned film.