Yukina operates the Koutetsujou's steam locomotive, the Iron Fortress, as its primary driver. Originally an apprentice, she took command after her mentor perished in a Kabane attack at Aragane Station. Sixteen years old, she has short pink hair and green eyes. Yukina maintains a quiet, calm, and reserved demeanor, though she speaks more readily with the mechanic Sukari.

Beneath this reserve lies a deep concern for others, shown through her protective actions toward Ayame Yomogawa and her help caring for orphaned children on the train. She remains composed under pressure, demonstrating focused professionalism. Yukina possesses notable physical strength, evident when removing outer garments to boost locomotive speed revealed developed musculature. Her technical expertise includes advanced train operation, such as overriding pressure limiters and performing complex maneuvers during crises.

During the Unato conflict, Yukina played a key role against the transformed Miyuki Komai attacking as a fusion colony. She devised and executed a tactical plan: accelerating the train toward a dead-end tunnel and coordinating with Sukari to fire the cannon at the precise moment, collapsing the tunnel onto the pursuer. This action significantly neutralized the threat. Throughout the engagement, her operational decisions consistently prioritized passenger safety and mission objectives.