Born on November 4, 2003. In 2018, RUI won the grand prix of "LDH Presents THE GIRLS AUDITION". In 2019, she sang "Lilac", the theme song of "Bewitched" which is a part of the movie "That Moment, My Heart Cried -CINEMA FIGHTERS project-". In 2020, she sang "Ichirin no Hana" and "Kareyuku Koe", the soundtracks of the movie "Our Story". She also sang "Day Dream", the theme song of the movie "My Blood & Bones in a Flowing Galaxy" released on April 9, 2021.