The recreation of "The Witches", that was the aim of "Project Leviathan", reviving a race of beings capable of, for one thing, raising and lowering the temperature of objects (which was called 'Maxwell's Demon', which was based upon a thought experiment by Scottish physicist James Clerk Maxwell). There were many subjects created for that purpose, and only two survived; Ellis and L.A. But for some reason, only Ellis had the promise of achieving Maxwell's Demon, and project director Douglas Rosenberg placed her into the care of the project's scientific head, Dr. Heinrich "Heinz" Schneider.
At first, Ellis showed little progress in her powers, but soon began to exhibit them, partly due to her fears about the constant tests Dr. Schneider was doing on her, although she had little progress in controlling them. Dr. Schneider then decided to ease up on the tests, showing Ellis the outside world. Because of this, Ellis gradually fell in love with him. However, Dr. Schneider began to get suspicious of Rosenberg's true motivations about Project Leviathan, and decided to flee with Ellis. But on the evening the two were to celebrate leaving their remote home, Dr. Schneider was shot and killed by Rosenberg from a distance through an open window. Ellis, who was in front of Dr. Schneider, was splattered with blood, and subsequently was made the prime suspect.
The trauma of seeing Dr. Schneider die caused Ellis to subconsciously blot-out the events of the murder, which included her identity. Feeling an urge to travel south, she found herself in a town in Mexico, earning a meager living performing card tricks. It was there she met the bounty hunter Nadie, her cover being to collect on the bounty on Ellis' head, but in reality she was hired by Jody Hayward (who was one of the surviving Witches) to safeguard Ellis from other bounty hunters. Rosenberg was also watching Ellis, using L.A. to monitor her and the development of her powers - a task complicated by L.A falling in love with Ellis, as well as using Ricardo and Lirio, both to watch the girls - and for Ricardo to discipline L.A. when he got out of line.
Besides Maxwell's Demon, Ellis also has the ability of levitation. She can draw out objects from human bodies (shown when Nadie was wounded one day). However, the use of her powers is involuntary, often done under stress. Ellis is also bluntly honest, and is not in expressing her feelings, not only to others... but also about her growing affections towards Nadie.