A 45-year-old salaryman working at an unspecified Tokyo company, Father stands 165cm tall. Though lacking an official given name, he occasionally answers to the nickname Nishikata. He is the husband of Mother and father of Mikan and Yuzuhiko, commuting by train despite owning a blue hatchback coupe. Daily routines involve drinking beer, smoking, visiting pachinko parlors, and engaging with baseball.

Typically taciturn and steady, he operates at his own pace yet reveals expressive flashes—like scolding Mother over misplaced household items, including his favorite ear-pick brand. When intoxicated, he inadvertently brings home others' belongings: mismatched shoes, school bags, or even a large Santa Claus figure during his youth. Once, during rain, he took an expensive "Passion Rose" umbrella, prompting Mother to sew their family name onto it over their daughter's moral objections.

During extraordinary events like the lightning-induced body swap between Mother and Mikan, he provided observational and logistical support. Recalling specific incident details, he collaborated with his son to research celestial phenomena like the Matchoore Comet for reversal methods. His involvement extended to practical tasks like coordinating airport pickups amid the crisis.

Personality assessments classify him as an ISTP (MBTI) and Enneagram 9w8. Family relationships fluctuate between lighthearted embarrassment for his children during unconventional actions and quietly supportive crisis presence. He employs pragmatic problem-solving, often relying on his son's research and logic during complex scenarios like the body-switching ordeal.