In the light of day, the Knights of Walpurgis were a masterpiece of Slytherin stagecraft. They were the "Golden Circle" of Hogwarts—a collection of high cheekbones, perfect Prefect badges, and the kind of pureblood pedigree that made Professor Slughorn beam with reflected glory. To the teachers, they were the elite; to the rest of the school, they were a beautiful, terrifying wall of emerald and silver.