Ravonna is Kang the Conqueror's lover.
History[]
She was caught in the temporal anamolies and if not for Kang's technology would have been purged from existence. Kang traveled back to the 21st century to kill Captain America and prepare Earth's armies for the Skrull-Kree war all to save her. When the Avengers stormed Damocles, Wasp discovered Ravonna in her stasis tube.
When most of the Avengers had claimed the time drive, they prepared to send Damocles back to the 41st century and let Kang die there. Wasp then showed up and told them who Ravonna was and why Kang was doing this, which convinced them to not send them back. Reed Richards and Hank Pym worked on getting her out of the tube while not removing her from existence. The tube was kept in the Baxter Building and was strong enough to withstand Doombots attacking.
Since she is under the care of the Fantastic Four, they have yet to tell the Avengers whether they are making any progress in keeping her alive.