Yui is a mysterious girl in Sword Art Online.
Yui is created by Reiki Kawahara as the main character in Sword Art Online that is based on the light novel. She first appears in Sword Art Online episode 11, The Morning Dew Girl.
Yui is a cute girl who has long black hair and big eyes that are colored deep black. In her pixie form in ALFheim online, she is a small, cute pixie who wears a pink, Tinkerbell-esque outfit.
At first, she acts like a curious child, and she is compassionate about her mother (Asuna) and father (Kirito). After her death in Sword Art Online, she reappears again in ALFheim. She is still curious, and she often asks Suguha, awkward questions.