Ui belongs to Trinity General Academy and is the chairman of the library committee. She loves books and is also a bit of a misanthrope, although it is unclear which of the two comes first. She is particularly fond of old books, and spends her days in seclusion, deciphering and managing old tomes at a place called the "Antiquarian Bookstore". Her intellectual curiosity and her knowledge of antique books are first-rate, and she is even called the "Sorceress of the Antiquarian Bookstore" by others.

Head of the Library Committee

She is one of the characters from the gacha game "Blue Archive" created by Nexon. In the game she was founded in an abandoned building at the Ruins, it's impossible to retrieve any information about her origin nor her age. She is now a mysterious member of the Millennium's Game Development Department. Currently she enjoys playing games with the members: Yuzu, Momoi and Midori and become a serious game fanatic. She wields a Railgun as her weapon. She refers herself in a third-person manner.