Tomio Tamura, known as Grandpa Tommy or Tomii, is Kazuma Tamura's grandfather and Makoto Tamura's father. This 70-year-old historian lives in a log cabin, dedicating himself to studying old folk tales and fairy tales, with a special focus on Great King Enma's scepter.

He expresses his creativity by inventing mechanical robot dolls, such as the "Mechanical Music Doll," which influences people's behavior through its music, and the "Mechanical Dessert Doll," designed to create various desserts.

He was the husband of the late Sayuri Tamura (nicknamed Sally), who appears only in flashbacks and old photos. A past incident reveals that Sayuri's sister, Mariko, deceived Tommy by falsely claiming Sayuri disliked him, ultimately bringing them together. Makoto's aunt, Jun Koshifubuki, is part of his extended family.