Komasan is a komainu, more closely resembling a shiba inu with long, blue fiery eyebrows that look similar to hitodama flames. Throughout his body and head, he has ivory-colored fur with a light blue stomach, tail, and inner ears. His eyes are a lime-green color and he has red swirls on his cheeks and hips. Komasan's eyebrow flames are actual fires, and rarely cause burns. He also can control fire, to a degree, and can summon will-o'-the-wisps to set fire to his opponents. However he's largely not a fighter, preferring peaceful interactions and making friends.
He carries a green furoshiki (a cloth that can be wrapped, which is used for storing and carrying items) with a white spiral pattern wrapped around his shoulders. Little is known what he carries inside it, but in Komasan in the City: The Turnstile, there have known to be various everyday objects inside. In The Koma-Santa Clause, he was given a green sling pouch from Komajiro after he helped deliver the presents for Christmas and uses it for storing extra things. That would become his appearance in later video games, starting from Yo-kai Watch 2. This appearance is somewhat retained in his human disguise.
When Komasan puts a leaf on top of his head, he can transform into a human for his disguise. His human appearance is of a male teenager with black hair, eyes with black pupils with a facial appearance resembling the original form of the Yo-kai, while he wears a beige blazer with a shirt, necklace and dark-brown pants. He sometimes uses it in the anime series, most notably in the Komasan In Love segments, even though in the Kaptain Komasan segments, he is seen in his original form to the viewers of the segments.
Komasan is a shy, yet curious Yo-kai that likes discovering new things. He was once a guardian at a shrine for centuries until it was demolished, leaving him to wander into the city and get used to modern life. In some of the video games, he's depicted as initially timid and cowardly, a point that earns him the mockery of Springdale's guardian Kyubi.
He is portrayed as a country bumpkin and usually speaks with a stereotypical country dialect of whatever language he's been dubbed in. In English this manifests as a Southern accent, while in Japanese it's the Nagano Prefecture dialect of Japanese, most notably seen with him adding the -zura suffix to his sentences (more or less the Japanese equivalent of a Southern accent). When excited, frightened, or surprised, he usually exclaims "Oh my swirls!" (Monge~! (もんげー！) In the Japanese version), though on several exceptions he says stuff like 'Oh my snake!' when being surprised by a large snake.
Komasan is sometimes uninterested in changing people's minds. In Komasan: 'Movin' On Up'!, when the president of the company Komasan was working at retired, he thought of it as a good idea.
Poofessor showed up in an episode and he shared some interesting facts with Komasan, but Komasan was more interested in enjoying nature, (he was catching butterflies at that moment) finding four leaf clovers, and sleeping.
When Nathan Adams summoned Komasan to stop Irewig in Yo-kai Irewig, he ended up getting inspirited by the centipede Yo-kai, however, the way he channels his anger drove him to work toward stopping whatever problem would tick him off (e.g, scraping all the gum off the street), to the point where he eventually forced Nate, Whisper, Jibanyan, and even Irewig to help him.
Whenever he serves as a judge in a contest, he has a strange way of deciding who wins. For example, in the Yo-kai Red & White Song Battle, Komasan chose the Red team as the winner because Jibanyan was red and happy while Whisper was white and unhappy.
In the anime, he has had a large number of mini-corners, starting with Komasan In the City where he tries his best to learn as much about the city as he can to present himself as a good role model to his younger brother, Komajiro. He pretends to be very knowledgeable about city life. However, Komajiro has a high capacity to adapt to the city and soon becomes a DJ at a nightclub. By the end of this mini-series, he'd accepted his general preference for the country, and retained Komajiro's admiration by saving him from getting beat up. They ultimately decided to remain in the city, taking up residence at a small riverside house.
"Komasan" is the "koma" half of komainu followed by the -san honorific.
Komasan is based on a komainu, a guardian statue halfway between lion and dog. Originating from Chinese guardian lions, they guard the entrance or inner building of Shintoist shrines. They usually come in male-female pairs, placed at each side of the entrance. Because of Buddhist influences, the right one's mouth is always open while the left one's closed, pronouncing "a" and "um", the first and last letter of the Sanskrit alphabet: together they form the sacred syllable Aum. Incidentally, these letters are the original names of Komasan and Komajiro's Alpha and Omega skills.
While Komasan is based primarily on a komainu, his leaf transformation and love of food are traits often attributed to tanukis.
Komasan's initial design during creation was "a friend like Jibanyan" taking notes from the latter's design except by giving a features of a dog, and eventually making the head into a bean-shape, which would depict his personality.
There's alternate artwork of Komasan, which depicts him with a thumb which he is never seen with in the games or anime.
In early episodes of the Yo-kai Watch anime, he has a slightly different-looking appearance compared to newer episodes.
In EP058, Komajiro says that he and Komasan are over 300 years old.
He was voiced by Melissa Hutchison in the first two seasons of the English-dubbed anime, and in the video games.
In the Portuguese dub, Komasan speaks with a Porto accent. As Porto is one of the most urbanized Portuguese districts, this contradicts his personality of a country bumpkin.
In M03, Komasan used Flurry of Fury after he released himself from one of the missiles Ultimate Robonyan fired, despite the fact that it is not one of his abilities.
Komasan and Komajiro are the only mascot Yo-kai to have a completely different name in the Korean localization.