Kumi-Kumi is first encountered as a mountain girl who saves Shinichi Watanabe from an avalanche and offers him soup. When he refuses it for being too hot, she begins to pursue him persistently throughout the series, ultimately marrying him in the final episode.

After their marriage, the couple adopts a ten-year-old girl named Poemi Watanabe, and they establish a family life together. This domestic peace is shattered by an assault from an alien assassin designated Alien #1, who attacks their home. Kumi-Kumi, Nabeshin, and their robotic pet dog are crucified and left for dead.

Kumi-Kumi survives the attack and uses her expertise in acupuncture to resurrect Nabeshin, revealing that death is not a permanent condition for them.

In a later paradoxical twist, the two alien henchmen behind the assault are exposed as Nabeshin and Kumi-Kumi in disguise, despite those same aliens having been responsible for their deaths—a contradiction openly acknowledged within the narrative.

Kumi-Kumi has brown hair of shoulder length and brown eyes. She commonly wears a dress and accessorizes with a ribbon and earrings.