Mr. Tachibana works as a salaryman in downtown Tokyo, commuting daily by train. He owns a blue hatchback coupe for personal use. He displays typical characteristics of a middle-aged Japanese working man: regular beer drinking, smoking, visits to pachinko parlors, and an interest in baseball.

Born in Ōita Prefecture, he retains a country accent despite his urban life. His childhood nickname was "Banban". He married Mother through an arranged omiai process, despite her earlier attachment to a childhood friend. His mother died shortly before his son Yuzuhiko's birth, an event that caused him visible grief—a rare display of emotion since his marriage.

Typically taciturn and stoic, he communicates sparingly, often in single words or short phrases. He maintains a calm demeanor and values quiet, clean surroundings. During his Sundays off, he contributes to household tasks, demonstrating reliability in family matters. He shows nostalgia regarding his children's younger years and exhibits a natural affinity for handling babies.

His problem-solving ability emerges during family crises, such as collaborating with Yuzuhiko to address a supernatural body-swap incident between Mikan and Mother. While generally reserved, he harmonizes effectively with his wife in managing household dynamics. His interactions reflect a consistent preference for practical actions over verbal expressions.

No official given name is documented, though he uses the nickname "Nishikata". His height is recorded as 165 cm.