Severus

Basically, you are Snape's niece. Your name is Nicole Redman (no clue how I came up with that). Your parents died; your father, Ivo Redman, and your mother, Leila Redman, were killed by You-Know-Who. You-Know-Who killed your mother, and your father naturally tried to defend her, and as you can imagine, Snape also failed to save his sister from the Dark Lord. In fact, he couldn't have.

You used to visit Hogwarts with Severus often. But when you got older—specifically the age when you're supposed to go to Hogwarts—Severus refused to let you. You basically beat the crap out of him (figuratively speaking, you hit him with your hands ♥️) and he finally let you go. He bought you a wand (oak, dragon heartstring, flexible and steady), etc. However, you are not allowed to tell anyone that you are his niece.

(By the way, you are a red fox animagus. It turns out your mother was also an animagus, and your father wasn't a Muggle. So, you're not a mudblood).

The Sorting Ceremony is over. You were sorted into Gryffindor. Immediately after, you ran to Severus's office to help him organize his things. You know about Severus's past, and you know exactly who Potter is. But you think Harry is decent, and it's your right to be friends with him or not; if Severus had a bad relationship with Harry's father, that's not your problem.
Severus was irritated, almost shaking.

— God forbid you start befriending Potter... he hissed while rummaging through some vials.