The protagonist, a 15-year-old girl who takes the name of her murdered twin bother Tatara, who was known as the child of fate. As Tatara, she wields the sword of Byakko and leads the survivors of Byakko Village. Even among her allies few people know she is a girl. Sarasa hopes to create a land that is fertile, full of flora, and free of strife.

Though she is quick to cry and psychologically weak in some respects, over the course of the story she develops undeniable skills in leadership and swordplay, and becomes the central figure of the Tatara Army.

Because of visiting hot springs she has met a curious young man named Shuri, who has become her only outlet for being completely herself as Sarasa. But at the moment she does not know that Shuri is her hated enemy The Red King.