Complex sentence: During "In Perfect Harmony" it is revealed she used her fame to create rules that when vampires feed from humans they can never kill or sire and the vast majority of vampires follow these rules for the easy food.
Split into simpler sentences: During "In Perfect Harmony" it is revealed she used her fame to create rules that when vampires feed from humans they can never kill nor sire. The vast majority of vampires follow these rules for the easy food.