Harry Potter: 10 Hardest Spells To Master

In Prisoner of Azkaban, to protect Hogwarts against the feared threat of escapee Sirius Black, Dementors were sent to the school. However, the only thing the students ultimately needed protection from were the magical prison guards themselves.

After Harry encountered a Boggart in the shape of a Dementor, Professor Lupin decided to bring him in for some personal tutelage. The Patronus Charm, the only known defence against Dementors, was never taught on the Hogwarts curriculum because it was simply too difficult to master.

To cast a Patronus, there is a great deal of concentration, determination, and skill required. The spell only works if the witch or wizard can focus on their happiest memory. The happier the better. Of course, this can be incredibly difficult when one of Azkaban's guards is literally trying to steal the joy straight from your soul.

For anyone to cast any kind of Patronus is indeed a special talent, due to the focus required on both the memory and the spell at the same time, but a full corporeal Patronus is considered almost miraculous. This is where the charm takes the shape of an animal, and is a great deal more powerful than the non-corporeal wisp of magical smoke, though this is still deemed as a great achievement.