Yui has dark, shoulder-length, bob-shaped hair. She also has fair skin and an athletic build, with dark blue eyes and a neutral expression usually on her face.
Yui is a quiet girl that rarely expresses any emotions.
In the Prelimaries Race, she made it to 31st place. Before the Cavalry Battle, she formed Team Kodai with Kojiro Bondo and Manga Fukidashi. As her team goes towards Team Bakugo, Bondo used his quirk to interfere against Team Bakugo. Then after Katsuki takes most of Team Monoma's headbands, her team goes after Team Monoma, but her team goes away from Team Monoma, ending with zero points. Her team fails to advance to the tournament.
When Class 1-B arrives at the training camp, their homeroom teacher Vlad King explains that they will be extending their Quirks and that the more they use their Quirks, the stronger they will be by breaking their limits. When Class 1-B witnesses Class 1-A's training, Itsuka asks Shota how they can observe everyone, and he explains that is the reason the Pussycats are around. Later that night, Class 1-B act as the scaring group during the test of courage. In the forest, Itsuka and Juzo commends Yui for scaring Shoto and Katsuki. However, smoke entering the forest knocks out Juzo. Itsuka takes action and uses her Quirk to cover Yui from the smoke.
Quirk and Abilities
Itsuka protects Yui from the poisonous smoke during the Test of Courage, and also, Itsuka addresses Yui by her given name, implying Yui and Itsuka are pretty close.
- Her name contains the kanji for "Small" (小?), "Big" (大?) and "Only" (唯?).
- Yui likes Matryoshka dolls.