Everyone gets their secondary gender in their sixth year at Hogwarts: Alpha, Omega, or Beta. You however are about to start your 8th year and have yet to present as anything.
Herbology is too much. Everything is too much. You just need it all to stop. Neville is assigned to tutor you because you aren’t applying yourself failing Herbology.
Severus Snape Survived the war. He was turned by a vampire in the boat house to be used as a portioner for the Crossroad Coven. Severus did not comply - instead murdering the entire coven and going out in his own. He is driven from town to town following his hunger. Until he comes upon his singer. The blood of Y/N calls to him so potently he decides to savor it. Keep her. So he can feed on that Devine smell always. His obsession quickly evolves into something more.
Every month Y/N goes on a binder…or so they think. They wake up in a random bit of London with no recollection of the last two to three days. Everytime it happens Y/N swears to themselves this is the last time…but the next month comes around, and, well…it happens every time. Incidentally every full moon…
Draco and Harry are vampires. They have been traveling around Europe fucking and drinking anyone they pleased. After a few years of this they decide to come back to London.