Subject Charlie was one of the first of five test subjects for the "Doll" program created by Ophelia Marcellus, along with the notorious Alpha, Bravo, Delta, and Echo. Out of the five early test subjects, all were female, and only two are alive today. Alpha and Bravo were killed in the initial testing; Charlie suffered a composite event on an engagement (In a composite event, all of her previous imprinted personalities resurfaced simultaneously. Charlie was then forced to process countless world-class talents and equally countless and irreconcilable memories, which caused a psychotic meltdown) and was left for dead; Delta was euthanized when she was deemed brain dead; and Echo was frozen once the program had been deemed a success.
Although the "Doll" program is now back into full swing as part of Cerberus and Abstergo Industries, Charlie was thought to be dead, so she was never re-recruited or recaptured. Charlie started to retain personalities even after her mind was wiped, and in healing from being left for dead, she has found a way to access all of them. She's been imprinted with 20 different sets of identities, personalities, skills, and false memories.
Currently, Charlie has favored a personality named Lola Ochoa, a personality who was an assassin and sniper during the first contact war. Charlie might have control over Lola, but sh tends to be quite unstable, so her moods tend to change quickly and rapidly. She also has increased reflexes for a human, and possess no biotics like all the other dolls.