The Anita Blake series is a novel series written by Laurell K. Hamilton. It has also been adapted into a comic. Anita Blake is a work-for-hire necromancer living in New Orleans. All manner of supernatural being live opening in her world, and when one of them kills someone she's the professional called in to take them down.
Melanie is a lamia, possibly the last living one, and occasional antagonist of Anita's. In Circus of the Damned she is an ally, or perhaps a pet, of the oldest living vampire, Mr. Oliver. She also assists the vampire Alejandro in an attempt to overthrow the ruling vampires of New Orleans. She lures Anita to a remote cave where Alejandro can turn Anita into his servant, but Anita gets free and kills the three members of Melanie's harem. In a moment of bickering between Melanie and Alejandro Anita is able to escape the cave to daylight, leaving the lamia trapped in a too-small hole.
She reappears, none the worse for wear, along with Mr. Oliver in a contest with Jean-Claude for dominion over New Orleans. She is seeming killed by wounds to the human parts of her body, but recovers even from that, as apperantly lamia are truely immortal. After Mr. Oliver is killed she is hired by Jean-Claude as a ticket seller for his local circus.