Gramma, known as Obaa in the original Japanese version, serves as the primary guardian and maternal grandmother to the young protagonist Yuna Kamihara. She lives with Yuna on the fictional Izayoi Island, part of the Ryukyu Archipelago, and assumed the role of Yuna’s caretaker following the death of Yuna’s mother in a typhoon. Her late husband, whose name is not revealed, was the founder of the karate dojo that Yuna would later inherit, and he also gave Yuna a protective moonsand charm before he departed. Yuna’s father, who is Gramma’s son, is a marine biologist who is frequently absent due to his work, leaving Gramma as the stable and consistent figure in Yuna’s daily life.

Gramma is characterized as a wise, kind, and spiritually attuned elderly woman. Her most distinctive trait is her unwavering belief in the yōkai, supernatural spirits that inhabit the nearby Chitama Forest, a conviction that sets her apart from most other human residents of the island. This deep-rooted faith in local folklore and tradition is a core part of her personality and guides many of her actions. For instance, she is the one who introduces Yuna and later Stitch to the Chitama Spiritual Stone, a mystical artifact that maintains the lifeforce of the yōkai and has the power to grant a single wish to anyone who successfully performs forty-three good deeds. Her wisdom and knowledge of island traditions also enable her to resolve conflicts between the yōkai themselves, such as a dispute between Kijimunaa and Tachicchu over a stolen tree.

Within the story, Gramma’s primary role is to provide stability, guidance, and a nurturing home environment. When the extraterrestrials Stitch, Dr. Jumba Jookiba, and Agent Pleakley arrive on Izayoi, she welcomes them into her household without hesitation, extending her familial acceptance to them and reinforcing the series’ theme of ʻohana. She is often seen maintaining the household, offering moral and cultural instruction, and serving as a calm anchor for the more chaotic adventures of the younger characters. In one episode, she reprimands Yuna for dismissing Stitch’s attempt to make her happy, demonstrating her role as a moral compass who ensures kindness within her family. On another occasion, she celebrates her birthday with a traditional wind chime that Yuna and Stitch make for her as a gift.

Gramma’s key relationships are primarily defined by her family. Her bond with Yuna is the most central, with Gramma acting as her loving guardian and teacher of traditional values. She also has a significant relationship with Stitch, treating him as a member of the family from the moment he arrives. She is patient with his destructive tendencies but also firm, reminding him that selfish acts will not be rewarded by the Spiritual Stone. Her acceptance of Stitch is unconditional, and she even recognizes his handwriting in a forged letter he writes to her. While her involvement in the main quests lessens as the focus shifts to Yuna and Stitch’s adventures, her presence is a constant source of support.

Gramma exhibits little to no significant character development throughout the series, remaining a consistently supportive and wise elder from her introduction to her later appearances. Her role in the plot becomes less prominent when Yuna moves away from Izayoi Island to Okinawa New Town to live with her cousin Tigerlily after her local school closes. However, she returns in the third season’s Christmas special, demonstrating her enduring connection to her family. Gramma does not possess any superhuman or magical abilities. Her strengths are her profound knowledge of local folklore, her spiritual awareness that allows her to perceive yōkai, and her sound, practical wisdom in managing her household and guiding her family.