YUNA/Black Yuna

YUNA (ユナ, Yuna?), also known as Black Yuna (黒いユナ, Kuroi Yuna?), is a supporting character in the Ordinal Scale side story and its epilogue, Cordial Chords. YUNA is an Artificial Intelligence (AI) created by Professor Shigemura Tetsuhiro[7] to attract Sword Art Online players to Ordinal Scale as an augmented reality (AR) idol for his plan to revive his late daughter, Shigemura Yuuna.[1][3] YUNA is the first augmented reality AI idol in the Sword Art Online universe and she serves as the image character for Ordinal Scale, greatly contributing to the game's popularity.[4] In-game, she appears to perform one of her songs during event battles, providing buffs to the players with her songs, and is referred to as the game's Diva (歌姫, Utahime?).[4] YUNA's management had been entrusted to an entertainment company named «Ario Room» by the professor, although her schedule was effectively decided by Shigemura Tetsuhiro and Nochizawa Eiji. As an entity created based on Sword Art Online's artificial intelligence, YUNA's program requires access to the Sword Art Online server to function.[3] Following the Ordinal Scale incident at the New National Stadium, Shigemura Tetsuhiro ceded his management rights for YUNA to Ario Room and Kamura.[3] After the professor relinquished his rights to the AI, the new management created at least five copies of YUNA that operated concurrently. Unable to bear the idea of copies of her existing in the world, the original YUNA began accumulating errors that would have eventually led to her collapse. However, her programing was stabilised by a more advanced AI reproduction of Yuuna with Eiji's help.[8]