Yuzuru Arikawa, one year younger than Nozomi Kasuga, is her childhood friend and the younger brother of Masaomi Arikawa. During high school, the trio was inseparable until a rainy-day encounter with a mysterious boy transported them across time and space. Yuzuru reunited with Nozomi shortly after arrival in the parallel world but became separated from Masaomi during the transfer.

In this parallel world resembling the late Heian period, Yuzuru aligns with the Genji clan, fighting alongside Nozomi against the Taira (Heike). He serves as Ten no Byakko (Heavenly White Tiger), one of the Eight Guardians of the Priestess of the White Dragon. Functioning as a ranged combatant, he utilizes archery to target enemies in the rear row, a tactical role introduced in this installment. Despite being a first-year high school student, Yuzuru exhibits maturity and academic diligence. He practices archery and frequently displays worry and protectiveness toward Nozomi, harboring unrequited romantic feelings for her that he struggles to express.

Yuzuru's personal journey involves navigating loyalty to Genji while coping with Masaomi's absence, later discovering his brother fights for the enemy Heike forces under the alias Kaeri naifu. His development intertwines with Nozomi's repeated time-travel journeys using the White Dragon's power to alter fate. Accessing his dedicated route requires fulfilling specific "Affinity Barrier" events by selecting particular dialogue options to deepen his bond with Nozomi.

In the canonical sequel "Unmei no Labyrinth," Yuzuru returns with a new character portrait and outfit. He participates in resolving a new crisis involving memory loss and a magical labyrinth. His romantic route remains available, requiring players to rebuild intimacy from scratch and prioritize his events during key moments like the Christmas party to unlock his ending. Completing his route excludes progress with other characters, necessitating multiple playthroughs. Treasure boxes containing past events may appear if players transfer save data from previous games and maximize his affinity, though these require specific abilities like lockpicking to access.

Yuzuru also appears in the OVA adaptation, continuing to fight for Genji. His narrative arc involves grappling with Nozomi's pivotal choice between staying with Kurou Yoshitsune or joining Masaomi, reflecting the unresolved tension in his relationship with her.