Arcadia DeVille is a mutant who was discovered and kidnapped at a young age by the Damocles Foundation . The Foundation was in reality a front for the genetic offshoot of humanity known as the Deviants, whose racial genetic structure is monstrously unstable. Through the Foundation, the Deviants hoped to re-start their evolution and gain genetic stability. The Foundation experimented on Arcadia to increase and control her powers.
After years of torture, Arcadia escaped with the help of a more ethical Deviant, Ulysses Dragonblood, the brother of the Foundation's director Odysseus Indigo. The two were hunted by the Foundation's strike force, the Sword. Eventually reaching Kentucky, Arcadia and Dragonblood encountered the mutant hero Cannonball, who was on leave from the X-Men to visit his family. Cannonball tried to help, but was overcome. Luckily, Cannonball's former team, X-Force, arrived to help drive off the Sword. During the battle, Arcadia didn't know who to trust and thought X-Force were enemies, so she transmuted X-Force member Danielle Moonstar into an immobile substance. Finally, X-Force defeated the Sword, and Arcadia restored Moonstar to her true form, somehow changing Moonstar's powers to control cosmic forces, similar to Arcadia's own.
Arcadia and Dragonblood struck out on their own, but eventually met up with the criminal Sledge who had a history of fighting the Foundation. Sledge sent them to stop the Deviants from resurrecting what he called a Celestial Template, which would re-start their evolution. X-Force has also arrived to stop the Deviants, and Arcadia and Moonstar were able to destroy the Template with their cosmic powers, as well as stop the evil witch Selene from absconding with it.
Arcadia went her own way, but began to have nightmares about a bear pursuing her. Somehow the bear became real, and when she reached San Francisco looking for X-Force, the bear was gigantic and wreaking havoc on the city. When Moonstar saw the bear, she recognized it as the Demon Bear that had haunted her when she was younger and realized that Arcadia must have accessed some of her memories in their last encounter. She and Arcadia were then swallowed by the bear. Inside, Arcadia's doll Mary Weather guided them to the truth about the bear and their connection to each other. Arcadia and Moonstar pooled their powers to disassemble the bear, and when it was done, Arcadia had turned into the Queen of the Star Swords, a villain from her childhood fantasies and a powerful version of herself from another dimension. The Queen called four versions of Moonstar from other timelines to serve her and began creating a citadel that linked to all the realities in San Francisco Bay. Moonstar and X-Force finally stopped her with the help of one of the other Moonstars and Arcadia returned to normal. Arcadia and Dragonblood parted company with X-Force again to wander the country.
Arcadia possesses the mutant ability to manipulate cosmic forces in order to warp reality to her whim. The full extent and range of which remains unrevealed.