Papa Panda, a male giant panda, originally lived at a local zoo with his son Panny. After escaping, they discovered Mimiko's house nestled in a bamboo grove—a natural panda habitat. Upon encountering Mimiko, a girl living alone during her grandmother's absence, he learned she was parentless. He immediately proposed becoming her father, establishing an unconventional but devoted family unit with Mimiko and Panny. Their arrangement allowed daily zoo work for Papa Panda and Panny, returning to Mimiko after hours.

He exhibits a consistently warm, friendly personality with an approachable demeanor marked by a round physique and perpetual smile. Despite his caregiver role, his grasp of human tasks remains limited due to his panda nature. He demonstrated protective instincts and physical strength early on by forcing closed a rusted floodgate to save Panny and Mimiko from floodwaters—an act that cemented Mimiko's trust and secured zoo approval for their living situation.

In subsequent events, he maintained his routine of zoo work and evenings with Mimiko and Panny. Their domestic life featured adaptations like oversized household items, including a large toothbrush and dinner plate. During a catastrophic flood, he aided in rescuing a baby tiger named Tiny and other circus animals from a stranded train. His strength proved pivotal again when he halted the runaway train, preventing it from crashing into the mayor's residence and earning local hero status.

His character design and gentle, supportive presence for Mimiko served as a creative precursor to Totoro, sharing visual traits and embodying similar fantastical companionship for a child protagonist.