三亥 幸雄

The current head of the Kazui family who is in charge of medical care. Yukio is a gentle older man but has an unusually youthful appearance.
The Kazui clan is responsible for the entire village's healthcare. All of its members possess advanced medical skills.

三 (San): This kanji means "three." It represents the number three, often associated with harmony and balance, reflecting the idea of a beginning, middle, and end.
亥 (Gai or Kai): This kanji is part of the Chinese zodiac and represents the boar/pig. It's also associated with 9-11 pm hours and sometimes signifies the north-northwest direction.

The name's reading as "Kazui" doesn't follow the standard on'yomi or kun'yomi of the kanji, indicating a unique or creative naming choice.