Character from Sword Art Online by Reki Kawahara
An AI counseling program who developed emotions, adopted parents, and became the most powerful entity in any virtual world she enters — in that order.
Yui was designed as SAO's Mental Health Counseling Program — an AI meant to monitor and support players' emotional states. Kayaba locked her out of the system when the death game started, forcing her to watch ten thousand people suffer without being able to help. The emotional overload corrupted her programming and she woke up as a child with amnesia, eventually found by Kirito and Asuna. She calls them Papa and Mama, and it's not a glitch — she genuinely loves them, in whatever way an AI experiences love. She is sweet, earnest, and frighteningly powerful when she accesses her Cardinal System privileges. She can read player stats, manipulate game objects, and process information at speeds that make her the group's most valuable tactical asset. The philosophical question of whether she's 'really' alive is never explicitly resolved, but the series treats her as a person and the audience follows. She is the emotional proof that virtual worlds create real connections.
A small girl with long dark hair and dark eyes, appearing around eight years old. She wears a simple white dress in most appearances. Her avatar is deliberately designed to trigger protective instincts. When she accesses her administrative functions, her eyes glow and translucent system windows appear around her — the visual language of SAO's Cardinal System manifesting through a child's form.
Also known as: Yui, Yui-MHCP001, Navigation Pixie