So I have lore on Sliverhoof so pretty much when she was a filly she was friends with another pegasus but that pegasus eventually became a Alicorn and had more stuff to do so they stopped being friends and because of this Sliverhoof decided to erase the alicorn species not by killing them but by removing there alicorn hood making them normal ponies again, she hasnt found a way yet and since shes only a pegasus shes constantly looking for a unicorn to help her achieve her goal