She has light-colored wavy hair that goes down to her shoulder blades. Her most noticeable feature is a burn mark on the right side of her face that stretches from her forehead to her cheek. 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.
She is often seen wearing a yukata.
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. She is very civilized and taught Gabimaru basic manners when they became a couple.
Yui was born as the daughter of the Iwagakure Chief. Being born a female, Yui was not trained in the way of the ninja 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.
- "Let's always make sure to observe all the little normal everyday rituals. So we can be wed, not as pawns, but as people."
- "You're not empty."
- "You are a kind and gentle man. After all, you're the only one who doesn't recoil from a face like mine."