Underswap sans x reader

About a year ago monsters were released from m.t ebbot and since then there is a school called underhigh for monsters and humans your real name is (Y/N) but you have the nickname nightshade because your like gore people are afraid of you but one day you see a monster being bullied so will you. Help or let him get hurt also your really mean and a good fighter you have dark blue and black hair and often where a necklace with black wings on you are also a hybrid between fox and human but choose to hide you can change into a fox or human with ears and a tail but the ears are red and black when you are a fox your belly is white the rest is red and black

Srry long description hope you like