I just got a much scarier thought.

What happens if C.A.I.S. takes over the body but each time it is killed she recreates the corpses and makes it immune to whatever killed her. After years of being killed she goes insane and just starts attacking everything. Unable to truly stop her we sent her away on a ship but she gets caught in some kind of time field and it sends her back in time. Over the years she changes and no longer looks human and eventually lands on earth but this time several years in the past and when people see her, they call her... Doomsday!