Yui has light-colored wavy hair that goes down to her shoulder blades. Early in her marriage, she used her bangs to hide the scar, but upon Gabimaru's request, she has since tucked them behind her ears. Her most noticeable feature is a burn mark on the right side of her face that stretches from her forehead to her cheek.
Yui is very kind, caring and gentle. She truly loves Gabimaru and believes that he is not completely emotionless as people make him out to be. She accepts the fact that he kills people and is not terrified being around him. Yui is also shown to be wise as she gave Gabimaru words of wisdom on why he should relax his body while giving him a bath. She is very civilized as she taught Gabimaru basic manners when they became a couple. Gabimaru also noted that Yui is not so petty to become angry at her husband for worrying about another woman.
Yui was born as the daughter of the Iwagakure chief. Being born a female, Yui was not trained in the ways of the shinobi and instead lived a semi-normal life within the village. At some point, during her time with her father, the chief burned her face to make sure that she gave up on her dreams of ever living a normal, peaceful life as a woman. After Gabimaru, Iwagakure's strongest shinobi, proved his worth to the chief, Yui was forced by her father to marry him. The two then came to love each other as their days went by. Wanting to give his wife a peaceful life, Gabimaru came to the village chief requesting to abandon his duties as a shinobi, resulting in him being betrayed by the village and handed over to the authorities to be executed. After hearing news of her husband's captured, Yui went into a state of depression and refused to speak to anyone or eat as she waits in hopes for Gabimaru's return.