Komajiro evolves into Komiger starting at level 35. As of Yo-Kai Watch 2: Bony Spirits and Fleshy Souls, it evolves into Komiger at Level 33.
Komajiro is a Komainu who more closely resembles a shiba inu. His fur is ochre-colored with a cream patch around his muzzle and stomach; his inner-ears and tail are a darker shade of ochre. He has light blue eyes and brown swirls on his cheeks and hips. Similar to his brother, he has long, brown, flaming eyebrows which resemble Hitodama flames. He also carries a blue pouch adorned with a swirl pattern.
Komajiro is similar to Komasan in that he's curious and optimistic. Though unlike his brother he adapts much quicker to urban life to the point that it renders Komasan a tad jealous. He picks up city lingo, smartphone skills, and even manages to become a DJ at a nightclub where he adopts the nickname of KJ, gets a girlfriend and still expects more from his brother.
Despite being more skilled than his brother he still sees Komasan as impressive and inspirational to him. He and Komasan live together in a small house and the pair regularly go out on adventures around the city and beyond.
Komajiro's Yo-kai Cam tip implies that whomever he inspirits can't seem to find what they're looking for.
During Yo-Kai Watch Busters the three were shown to be part of Komajiro's band.
In the anime
Komajiro was mentioned by his brother when he came to the city in EP007, and was waiting for him, but never got the chance to find. He officially appeared in EP009, when the two brothers meet each other.
Komajiro is mainly featured in the mini-corners with Komasan, although appear in Nate's segments.
In EP027, Nate sees Komajiro with Komasan during the sale of the Yo-kai Watch Model Zero in Yo-kai-lifornia.
In EP056, Komajiro hitches a ride with Komasan when Nate summons Komasan to deal with Wantston.