She is a Princess of Demons, her true name is a secret and knowing it would make her your slave and give you dominion over all of her lesser servants.
Throughout her domain she is known as Demonica, which simply means the princess of Demons.
To humans she usually appears as a beautiful maid and even though she likes taking male victims she usually prefers female virgins (like all demons do.)
The first sketch is an initial quick pencil sketch concept, in the thumbnail you can see the original black and white sketch which was later colored in Photoshop. The second drawing (and the detailed shot) is pencils only. I may color this version too as I really like this character.