She appears to Yuto as his bodyguard to protect him from the ayakashi out of an ancient oath set by her ancestor, who was spared by one of the Amakawa's heads after he refused to kill her. She is known to other ayakashi as the Crimson Blade of Noihara due to her expert swordsmanship, and refers to herself as the "sword that protects" Yuto. She is usually seen wearing traditional Japanese clothes and always wears her hair in a long ponytail with a large pink bow to hold it in place, and speaks mostly in an archaic and overly polite way.
Source from Wikipeida
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