The Patronus Charm (Expecto Patronum) is the most famous and one of the most powerful defensive charms known to wizardkind. It’s an immensely complicated, very difficult spell that evokes a partially-tangible positive energy force known as a Patronus (pl. Patronuses) or spirit guardian. It is the primary protection against Dementors and Lethifolds, to which there is no other protection.
- Expecto Patronum