Yuki hails from a Post-Restoration world where her lover, Daisuke, dies in the World Restoration event led by Aiko. Haunted by grief, she recovers her memory and resolves to prevent his death. She travels back in time intending to kill the man fated to reincarnate as Aiko, aiming to stop the World Restoration before it begins.

Her background originates in the World War II era, where she was a well-born woman involved with Japanese officer Karino Daisuke. A distinctive physical marker, a star under her left breast, features in this earlier timeline.

Following time travel and interventions from others, an altered timeline emerges. In this new reality, Yuki becomes the wife of Gonza, her former servant. This shift results in a peaceful existence, free of the religious and nationalist conflicts that marked her original history.