Obaa, whose name is simply the Okinawan word for grandmother, is the matriarch of the Kyan family in the anime Haitai Nanafa. She is the grandmother of the three sisters, Nanafa, Nanao, and Kokona, and she runs the family business, an Okinawa soba restaurant called Kame Soba, where Nanafa often helps out. Within the household she is the most senior figure and the de facto head of the family, the adult presence who holds everything together.

Her personality combines kindness with wisdom. She is described as gentle and as a person of good sense, but she also has a strict side that comes out when the situation calls for it. This firmness is most often directed at the supernatural houseguests, the mischievous tree spirits known as kijimunaa, who have taken up residence in the family home along with the shisa spirit Iina. When their mischief goes too far, Obaa disciplines them using karate techniques, and she is strong enough to put even spirits in their place.

Despite being well over eighty years old, Obaa is extremely energetic and vigorous. A running joke in the story is the rumor that she has a boyfriend in his twenties, which highlights how lively she remains despite her advanced age. Her energy, quickness, and practical wisdom together make her the calm, stabilizing presence in a household that is frequently thrown into disorder by spirits and other supernatural events.

Her motivations are rooted in her family and her work. As the owner and operator of Kame Soba, she keeps the shop running and preserves the family's everyday life, while her disciplining of the spirits serves to protect the household and maintain order. In the story, her role is that of an authority figure and caretaker: her granddaughters and the spirits generate the comedy and conflict, and Obaa is the one who restores order and keeps the family grounded when events get out of hand.

Her most important relationships are with her three granddaughters and with the spirits who stay in her home. She tolerates the spirits as guests but does not hesitate to correct them, and her karate is used primarily against them when they cause trouble. Toward her granddaughters she is the dependable family elder who runs the shop that anchors their shared life.

The series does not give Obaa a dramatic personal arc; she appears throughout as a consistent and enduring figure who remains essentially unchanged while the supernatural incidents and the other characters come and go. Her notable abilities reflect this stability: considerable physical strength and martial skill for someone her age, enough to handle supernatural creatures, combined with the wisdom, firmness, and seemingly inexhaustible energy that allow her to manage both the ordinary demands of running a soba shop and the extraordinary events brought on by the spirits.