Charlotte Wells suffers from dissociative identity disorder, a result of a traumatic incident where she was abducted and held captive for days. Only Dr. Richard Hanover manages to get through to her and when he triggers an episode, Charlotte ends up killing him. In the final episode, it seems that any trace of Charlotte is gone and one of her darker identities has taken hold. She joins Edmund and Louise on a murder spree, but all hope is not lost. We've seen Charlotte take control before and it's possible she can do so again. Maybe she'll be the downfall of Edmund in a future season?