Hiromi Sugita is a neighbor and classmate of the main protagonist, Takashi Sagano. She becomes involved in the central adventure after she overhears that Takashi is planning a journey to Wonderland to rescue Alice; upon learning this, she makes the decision to follow him.

Her personality is characterized as being rowdy and impulsive. Despite her boisterous nature, a significant part of her character is her deep concern for Takashi's safety, as she worries about him because he often engages in dangerous activities. This concern is further emphasized by an implied romantic affection for him. Her primary role in the story is that of a companion who joins the quest to rescue Alice, accompanying Takashi and their other friends through the various challenges they face. Regarding her development or any notable abilities, no detailed information is available.