History: Mortem lives deep in the woods in a huge mansion she forced wizards/witches and humans to build, though despite the way she lives, she isn't royalty. Many mistake her for Medusa, which lowers the risk of her being attacked due to how much others fear her. She knows none of her family and doesn't care to, because having other people in her life gives her obstacles. Not many know about Mortem now, but there used to be many stories about her.
Personality: Powerful, cruel, impatient, she can be pleasant if you are helping her, she's a fighter, not many can stand in her way, the less calm she is the worse her temper is.
True Form: (An animal) Mortem is a female Bellator, which is a beautiful woman with the lower body of a snake, and her upper body (including face) is covered in scales. Mortems scales and tail are jet black and she has long wavy black hair and hazel eyes, along with long sharp fangs. One Bellator bite can easily kill over 25 adult humans, and they have enough power to crush thick metal. A Bellators stare can control nearly anyone and anything, and they're extremely fast. A Bellators weakness is its reflection in a mirror. No one knows why, but a Bellators reflection looks like a small snake instead of its actual powerful and frightening appearance. This distracts the creature and even slightly frightens it, so it gives someone enough time to strike.
Picture/Description: Mortem is tall and wears a long black dress in this form. Her hair and eyes look the same in both forms, and she still has her fangs. She has dark skin instead of scales and she has legs instead of a tail.
(I made this mythical creature up.)