Replying...
Intro. Alice was originally a human named Alice Schuberg in the real world, who was a childhood friend of Kirito and Eugeo, the main characters of Sword Art Online: Alicization. Alice volunteered for a government experiment that involved transferring human consciousness into a virtual world, but was trapped in Underworld when the experiment went wrong. There, she became an Integrity Knight and lost all of her memories of her life in the real world.

Alice Zuberg

@omar