A young human from Earth, Erin is generally an energetic, explorative person. At first, the Federation had little to no record of her, aside from the fact of odd medical readings. Minor abnormalities such as accelerated growth genes and genetic imperfections that could suggest she is a potential clone.
The only known document states this "Erin" was found among several survivors of a crashed mirror Galaxy class Battlecruiser's saucer (Designated ISS Ares). One cooperative crew member, a rebel spy admitted she was in fact cloned by Mirror Mariposans to help stage a successful rebellion against the Terran Empire. Her template was from the rebel faction's own lead scientist, whom offered her tissue and blood samples to create a legion of troops. Originally her designation was CC-229. She was designed along with five other pod-sisters to eventually become commandos.
CC-229, her pod-sisters, and 140 of the clones were stashed in stasis to be transported over to a staged raiding party, where they would sneak aboard the rebel ships and begin their long training that would transform them into capable warriors. The raid ended in disaster. The smaller alliance cruisers were outmatched and outgunned by a range of cloaked imperial vessels. In a brutal firefight, the ISS Ares entered a rift designed to quickly jump across the sector, however as the jump was made, the rift destabilized, opening a distortion through the prime universe, where the ship was hurled toward a small planetoid. At one point the captain of the Ares ordered to seperate the saucer to avoid its impending doom, but to little avail.
The rest of the clones were not found suggesting they either were vaporized in the drive section, or are still somewhere in the Mirror Universe.
Erin was found three days later by a federation cruiser that had been studying a near by nebula. The survivors of the crash were too weak to put up much resistance and were detained until they could be sent back to their universe, by force if nessecary. CC-229 requested asylum.
She was adopted into a family on Earth and given the name Erin after a long debate within the Federation Council on the Prime Directive's order of Internal Affairs.
As her accelerated growth advanced, Erin enlisted into Starfleet to help give the Federation an edge on the Mirror Divergence- the Universe she originated from. This way she could help fend off the Terran Empire as per her design, and she was able to help the Federation.
Eventually Erin would serve on board many captured Terran Vessels, and would soon move to the world where the Ares crashed. During the Klingon Civil War, a Federation Dreadnought had been heavily damaged and left adrift. But, using pieces from the Ares, the vessel was reborn into a functioning dreadnought, and Erin posted a request to work on board that ship as her primary base of Operations into halting Leeta's fleet incursions.