Was it ever stated explicitly that Melanie is an avatar of the Slaughter? Because I think that the Desolation would’ve suited her very nicely.
She hurts everyone around her, damaging herself as well. It was not exactly out of a desire for violence and the need to kill. Her hostility was a result of her being… lost, in a sense. An animal, trapped and afraid, ready to gnaw its own leg off just for a moment of freedom. She was trapped by her own grief, unable to move past it.
Her anger consumed her, just as the flames consumed her unsuspecting father.
The anger was technically foreign; it came from the bullet lodged deep in her body. But as it ingrained itself deeper, she could no longer tell where the bullet’s anger ended, and she began. Maybe it had always been there, simmering quietly, waiting for an opportunity to set her ablaze.
Anger that burns you out, leaving just ash. An invisible force that burns you alive, destroys you from the inside, and yet it’s a source of warmth, of comfort, of familiarity.
Her trying to change for the better was like a phoenix rising from its ashes. A dangerous being, rendered by its own power into a fragile, helpless thing, with no feathers to make it feel that warmth again. What will you do now? Without that fire, that force which defined your very being?