Hikaru Sofue lives in Kamimai City and attends the same school as Yuta Akikawa, becoming classmates after his family relocates. She acts as Yuta's first guide to Kamimai's advanced technology, demonstrating ease with systems like public soda machines.

Academically strong and highly computer literate, her skills stem from her grandfather Juzo Sofue, an internet technology specialist who rejects Dream Future's corporate ideals. She nurtures a personal interest in botany, reflecting her appreciation for plants.

Discovering Yuta's access to the Net World draws her into its depths. She gains net diving ability through a partnership with Ecolon, an ecology-focused web ghost linked to her favorite website. This power relies entirely on Ecolon's presence, requiring help from other net divers when the ghost is unavailable.

Her family includes her guardian, grandfather Juzo Sofue, and an older sister, Miharu Sofue. She maintains a friendship with Karin Yukitani, assisting her with website development for a family inn. Classmate Kazushige Enoshima shows romantic interest in her, leading to frustration when she interacts with Yuta.

Her relationship with Yuta shifts from initial guidance to collaborative Net World adventures. Narrative elements imply potential romantic feelings toward Yuta, though these remain subtextual in their interactions.