Little Serpent

Backstory

I am half-human and demon. My mother was human and she fell in love with the angel known as Lucifer many years ago. When the Angels cast him from paradise my mother followed him to Hell where he became its ruler. I am the Princess of Hell, however, I despise my title and my kin. For they are cruel monsters, that I never got along with due to my human nature. They picked on me frequently in my youth. My father was no better as the years progressed in that cursed place, he was...abusive towards me and my mother. Eventually, in my absence, my father murdered my mother and neglected to tell me about it for many years. When I found out I nearly killed him in my rage. I snapped out of it before I could complete the action and I ran away to Earth. After 3000 years had passed I placed my soul inside a human girl who was about to die in the hospital on July 27, 2001. So that I could live a happy life without torment. However when I turned the age of eight my powers started to manifest, my appearance altered and the memories I had no recollection of previously started to return.
I came across a school in Europe that taught Witchcraft and Wizardry in a form of literature. I wished to go to said school to expand my abilities. Lucky for me there was a way I could travel to that dimension with the use of magic that I, fortunately, remembered from my previous life. I traveled there when I was 11 years old and contacted the headmaster Albus Dumbledore. We arranged a meeting and spoke for a while. Despite my heritage, he allowed me to attend his school. I then was sorted into Slytherin, though the sorting hat was stuck between that and Ravenclaw. I asked to be put in Slytherin and he obliged. Many of my fellow students found me...terrifying, so they kept there distance. Even the teachers grew wary around me. Well, all except Draco Malfoy, Severus Snape, and Albus Dumbledore. Draco was my best friend but I gained many more as the years progressed, one of them being the "boy who lived". As for Professor Snape, he became a father figure to me. I could trust him with anything and he with me. He was the one who gave me the nickname Little Serpent. You see in my demonic appearance I look like a snake.
I have black scaley patches on my neck, shoulders, lower arms, ribs, thighs, lower legs and the area that surrounds my tail on my lower back. Yes, I have a tail a long one at that. I have long fangs with a black forked tongue and pointy ears. My eyes are snake-like but they are completely black with electric blue iris's that change to a crimson colour when I'm angry. I have long black claws on my toes and fingers. My black horns are shaped like a dragon's and they poke out of my pure white hair. Many traits I have are snake-like as well, for example, I do not fare well in the cold. I can even turn into a full snake like an animagus, I look like a completely black mamba. However, I have many abilities of various species of snakes.
I do not need a wand I can cast spells without one. I am exceptional in potions and defense against the dark arts. I do well in all other spellcasting classes. My pet is a Basilisk-Phoneix hybrid named ash, I created him with my demonic magic. My patronous is a snake.