Dementor. It is known that Dark Wizards cannot cast a Patronus. The only Death Eater to cast a Patronus was Severus Snape and it was a Doe for his love of Lily Potter. In order to cast a Patronus, you need to think of a happy memory, and let it fill you up. Then cast the incantation.
- A corporeal form, it takes the place of an animal that best represents your emotions.
- X-Pect-Oh Pah-T-Row-Num.