A black rat and widowed father of two sons, Tata and Chichi, he raises them alone after his wife’s death following the younger’s birth. When human development destroys their riverside ancestral home near Tokyo, he must lead his family across hazardous landscapes—both wild and urban—to secure shelter before winter’s arrival, drawing on sharp survival instincts and unwavering protectiveness.

Guided by practicality and duty, he steers his sons through shifting dangers: forming uneasy alliances with a golden retriever, a reclusive brown rat from a library, and a Russian Blue cat, while evading hostile brown rat clans. His younger son’s snow-white fur, an anomaly among their kind, draws unwanted attention, forcing him to devise strategies to shield the vulnerable kit from predators.

His interactions reveal a stern but devoted mentor, balancing caution with pragmatism as he accepts aid from unlikely sources. Rooted in generations of river-dwelling ancestors, his identity remains tied to the disrupted ecosystem, fueling his resolve to safeguard his family’s survival despite unfamiliar urban threats.