Member of Girls Dead Monster, she takes over as lead after Iwasawa's departure.
Yui begins the series as a big fan of Girl's Dead Monster. She attended all of their concerts and admired the band's guitarist, Hisako.
After Iwasawa's departure, Yui becomes the rhythm guitarist and lead vocalist of Girls Dead Monster. During her audition, she rocked out a bit too hard and somehow managed to launch the mic stand into the ceiling. The cord wrapped around her neck, comically hanging her. It is brought up on one occasion that her guitar was bringing the band down.
Yui is nearly always hyperactive, and comes across as a big annoyance to Hinata. Because of this, they are always at odds with each other.
During her life, Yui was hit by a car and was left bedridden and with almost her entire body paralyzed. It is because of this that she wants to do as much as she possibly can during her time in the afterlife. Otonashi helps her achieve many of these, until she says that the one thing she really wanted to do was get married and be loved.
Hinata speaks up at this point, declaring his feelings for Yui and that he would gladly marry her. They comment that if they had met before they died, then they surely would have fallen in love. It's at this point that Yui disappears.
During the credits, Yui and Hinata are seen living happily together, possibly in the next life.