Mr. Yamada, a graphic designer often working from home, is a central family figure. His home office routine brings him into frequent contact with Chi, the family's adopted kitten. Their relationship faces challenges due to necessary but unpleasant tasks like vet visits and claw trims, temporarily straining their bond. Yet, he consistently shows deep fondness for Chi, actively working to mend things afterward with treats and patient coaxing to regain her trust.

As a first-time cat owner, he navigates a learning curve, such as when Chi mistakes his bag for a litter box, prompting him to get proper feline supplies. He joins family strolls with Chi and his son Yohei and engages in play like hide-and-seek. Chi's unpredictable nature often leads to comedic mishaps or disruptions, especially during energetic explorations of his workspace, testing his patience which he responds to with care.

He demonstrates adaptability during chores. Noticing Chi's unexpected fondness for the vacuum cleaner's brush attachment, he accommodates her quirk, letting her enjoy the brushing sensation despite initial confusion. He shares a supportive, affectionate dynamic with his wife Miwa and Yohei. They collaborate on Chi's care and fully integrate her into family life, even relocating to a pet-friendly apartment to ensure her permanent place with them, underscoring his commitment to her well-being within their household.