Batako-san serves as Uncle Jam's primary bakery assistant. Her Japanese name, meaning "Butter Girl," reflects her culinary role. She possesses a kind, optimistic, and hardworking personality, though occasionally forgetful. Her duties encompass baking with Uncle Jam, preparing sweets, cleaning, delivering goods, and performing laundry.

She skillfully stitches and sews, frequently repairing or creating garments. This talent extends to mending the damaged capes of Anpanman and other heroes, restoring their flight. Batako-san witnessed Anpanman's birth and helped raise him alongside Uncle Jam, forging a familial bond. She provides maternal care, replacing Anpanman's weakened head and repairing his cape.

Her appearance features rosy cheeks, black eyes, a small round nose, and spiky black hair that shortened during the show. She typically wears blue overalls over a white vest and a chef's hat concealing her bangs, revealing a bowl cut when removed. Early concept art explored an alternative origin where a young Anpanman discovered her as a baby in the woods, but this was discarded in favor of establishing her as older than Anpanman.

Batako-san shares a close bond with Cheese, naming him and advocating for his adoption. She often interprets his barking and partners with him on bread deliveries. Her connections with heroes like Shokupanman and Currypanman appear amicable. A past long-distance relationship with Omusubiman was referenced but not sustained. While resembling humans, official sources clarify humans scarcely exist in Anpanman's world.

Within the film "Yōsei Rinrin no Himitsu," Batako-san appears among the cast. Her established role remains consistent across spin-offs, OVAs, and other media.