Aura (アウラ, Aura) is an advanced AI that takes the form of a young girl whose white hair, skin, and garments give her a ghostly appearance. She is created by Harald Hoerwick to be a symbol of his love for his deceased lover as the daughter that could have been. She is meant to be the perfect AI that will take in collected player information by Data Draining the current AI control program, Morganna, though Morganna intentionally keeps Aura in her sleep-like state in order to not lose her purpose. After Morganna's plot to keep her asleep by using Tsukasa in .hack//Sign fails, she awakens and becomes hunted by Morganna's Phases to prevent Aura from developing Data Drain.
Aura manages to cultivate this power into an installation book, which ends up in the hands of Kite. Aura becomes Data Drained afterward, which causes her to be scattered throughout The World. She manages to communicate with Kite and other players through corrupted e-mails, which leads to the defeat of most of the phases. During the final battle, Aura is scattered again and merges with Morganna to complete the Ultimate AI. She becomes an omnipresent yet mostly silent force within The World for some time. She eventually sets out to perfect herself by interacting with the world by giving two players, Shugo and Rena, chibi versions of the avatars of Kite and Blackrose in a contest, and giving birth to another AI, Zefie. This is also to help Shugo, whose goal it to become a hero. Aura eventually disappears, which causes The World to decline. This leads to CC Corp developing Project GU in order to recreate her.