After Kaz sent Kent to kidnap Messenger in Double Sides, she was taken to The Demon's Fortress and injected with demon blood. Messenger managed to escape and was hiding in the forest in a fragile state when Blood Queen found her and tried to help her.
The demon blood injected into Messenger by Morgan Roots had started to turn her into a demon-like creature by that point. The medicine given to her by Blood Queen managed to keep her from turning into a demon, but the side-effects caused her to develop multiple personalities.
Messenger's personality changed after she developed into Melissa. She had turned cold and distant, no longer caring for her friends the way she did. She also had a new-found ideology, closely following that of Kaz and the Demon.
Due to being injected with demon blood, Messenger gained new abilities as Melissa. Melissa has keen senses of hearing, eye sight, and movement.
- Melissa, unlike Messenger before being injected with demon blood, was considered an enemy of Team Demon Light.
- Kaz used Melissa to his advantage since she was a loved member of Team Demon Light to caused greater harm upon everyone.
- Jen Devlin, having re-established contact with her daughter, Messenger, after years of not seeing each other, helped Team Demon Light find a way to cure Messenger before she was gone forever and only Melissa was left.