Ruon is a character in the 2.0 virtual reality world. A teenaged Teruki constantly escapes into the virtual world to have sex with her, but eventually confides that he would like to meet her in the 1.0 (the "real world").
Ruon comes into the real world despite rejecting Teruki's request originally, but, after giving him a kiss, he is a witness to her murder. After going to Asogi Consulting, Teruki learns from Mimi that Ruon was an AI created by Katsuyuki Kamiyama.
In Episode Four, Rin and the others learn that Ruon was created during "Project L'Isle-Adam" and is based on Kamiyama's daughter, whom he had killed when he copied her memories. The android later shoots Kamiyama and it turns out that Ruon had manipulated the military to get Teruki, the only person she cares about, as well as killing Yanagihara by a government sniper. She is destroyed while fighting Rin after falling out of the plane - and into its jet engine with her.