Bold and brash, Maëlys is someone that gets quickly noticed, be for her looks or her personality (she swears like a sailor, everyone is well aware of that fact).
Many say that she's a tsundere, but that's not true. She's angry for the fact she always got ignored because of her older brother, Gérard, with which she shares way too many similaries, and that anger made her someone difficult to approach.
When she was younger, she was more gentle and feminine. But her parents never cared that much for her (or her younger brother Jérémie, for that matter), Gérard was the star of the Victor family, and the younger siblings stayed quiet. But when he awoke his Dark Arts-related powers, he went mad with power and killed his parents. That was the breaking point between him and his younger siblings.
Since then, the three went for different roads, losing contact with each other.
Maëlys ended to quit her studies for become a pianist, she was too strssed during that period for deal with anything. She used to be an human, but thanks to a mysterious spell she read one time on a old-looking book, she turned into what she's now (gaining some height and muscles with that, making her quite imposing in the process).
She does have some minor anger issues and might leash out if under stress. There's a softer side of her, but no one managed to find out how it is.

She does have the power of technokinesis, allowing her to manipulate anything technologic around her. She does enjoy making electronic things go short circuit when fighting. Technology is a big part of her life, as her job is being an informatic hacker. She's often in her room, filled of computer screens, tinkering with informatic codes. (In reality, said technokinesis powers are a variant of the same powers that Gérard has, the three Victor siblings could master the Dark Arts, but only Gérard went along with that.)
She's a nocturnal person, preferring to be awake at night. nights passed in front of her super-computer while listening some hardcore or rave track. That's her way to relax, somehow.
Even with her "tsundereness", she does have a beloved. Said beloved being Mélodie, a drow she knew during her Conservatory years. The bubbly drow contrasts nicely with the bitter snake demon. Maëlys enjoys her presence in her life and she could listen her for hours talking even on the most inane things. She admires her positive outlook of life (even if she will never admit that).