Hiroshi Ichikawa resides as an orphan with his older sister, Utako, in Arama-sō, a modest two-story Japanese apartment building. This location functions as a key nexus in the human world for encounters with supernatural entities. Utako manages the household and cares for Hiroshi following their parents' absence.

Hiroshi befriends Tarou Kaibutsu, the prince of Monster Land, after Tarou arrives for training in the human realm. He frequently hosts Tarou and his monster companions—Dracula, Wolfman, and Franken—at Arama-sō. While conflicts arise against antagonistic forces such as the demon group Demonish and its assassins, Hiroshi typically observes rather than engages in battles.

His distinctive appearance features black hair, a yellow hat marked with the letter "H", a teal shirt, navy blue jeans, and light-colored shoes. This visual design remains consistent across all adaptations. In the live-action television series, Hiroshi maintains his role as a resident of Arama-sō alongside Utako. His classmates from the anime are absent in this version, replaced by new characters like Wolfman’s daughter and the apartment’s landlady.

Available sources detail his status as an orphan and human ally to Tarou’s group, but do not elaborate on significant character development, personality traits, or background beyond this. Relationships extending past his sister and Tarou’s companions are not depicted.