Live action TV
Description
Osoma is a young Ainu girl who lives in the Ainu kotan associated with Asirpa in Hokkaido. She is the daughter of Makanakkuru and the cousin of Asirpa on her mother's side, making her part of the same extended family as Asirpa and the elder woman Huci, who serves as grandmother to both girls.

Her name is a childhood name. In Ainu tradition, children are sometimes given deliberately unpleasant names in the hope of keeping evil spirits or misfortune away from them, and Osoma's name comes from the Ainu word for excrement. She is still young enough that she has not received the proper name that Ainu children are normally given once their personality and experiences become apparent. The meaning of her name frequently surprises outsiders, including Sugimoto, when they first hear it.

Physically, Osoma is a small girl with black hair and black eyes and thick, striking eyebrows that give her a mischievous, tomboyish appearance. Her personality is energetic, rambunctious, and highly curious, and she has little of the self-consciousness that older children develop. She is fascinated by the visiting Japanese men, particularly their earlobes, which look different from those of the Ainu, and she repeatedly calls them shinnakisara, an Ainu word for people with different earlobes. Her enthusiasm for play and her fearless approach to the newcomers are among her defining traits.

Osoma has a strong affinity for traditional Ainu children's games and toys. She especially enjoys seipirakka, clapper-like footwear made from shells, and she is also shown playing with the mukkuri, a small mouth harp, and the kisarari, a stick used to startle people by poking out from beneath a window. Through her play, she helps convey the texture of everyday Ainu childhood and material culture within the story.

Her role in the story is primarily that of a supporting presence in the Ainu village and its surrounding events. She helps illustrate Ainu customs associated with childhood, including the naming practice, and she takes part in the daily life of the community that shelters and cares for wounded outsiders. One of her most significant story functions is her connection to Tanigaki Genjirou, a matagi hunter who is brought to the village injured and nursed back to health there. Osoma assists in his care and quickly becomes attached to him, playing with him and staying close by his side. When Ogata and Nikaido arrive in the village pursuing Tanigaki, her quick actions help him survive: her timely behavior allows him to dodge a gunshot, and she fetches a rifle that belonged to the hunter Nihei so that Tanigaki can defend himself. When Tanigaki decides to leave the village to search for Asirpa, Osoma is deeply upset and cries at his departure. Following Ainu custom, she gives him a tekunpe, a hand-woven arm guard that Ainu women present to men they care for. She had managed to make only one of the matched pair, and Tanigaki promises to return and asks her to make the other one. When he eventually comes back after a long absence, however, Osoma has already turned her attention to a new crush, a boy of the village who is a son of Kiroranke, and she runs off to him instead, leaving her brief childhood attachment to Tanigaki behind.

Osoma is also closely connected to Huci, whom she is very fond of and visits often, helping with tasks such as gathering mountain vegetables and tending to young bears. Her bond with her cousin Asirpa is part of her place in the village as well, though her most developed interactions in the story are with the adults who pass through the kotan.

Her motivations are simple and childlike: curiosity about the strangers who arrive, enjoyment of play and games, and affection for the people who care for her and whom she cares for. She has no combat role, but she demonstrates notable cleverness, boldness, and presence of mind when danger reaches her home, and the tekunpe she makes shows care, patience, and initiative. Over the course of the story she develops from a carefree child into a slightly older girl experiencing her first childish crush, and her changing feelings reflect how quickly children grow within the world of the series.