The Patronus is a form of advanced magic which even the most qualified wizards can struggle with. Harry Potter was one of the youngest wizards to cast a corporeal Patronus, having been taught by Professor Lupin at the tender age of 13.
As Professor Lupin told Harry in Prisoner of Azkaban, the Patronus is ‘a kind of Anti-Dementor – a guardian which acts as a shield between you and the Dementor.’ It’s also ‘a kind of positive force, a projection of the very things that the Dementor feeds upon – hope, happiness, the desire to survive – but it cannot feel despair, as real humans can, so the Dementors can’t hurt it.’
The Patronus has two forms, non-corporeal and corporeal. A non-corporeal Patronus can appear as ‘a thin wisp of silver’ that hovers ‘like mist’. Whereas a corporeal Patronus has a form that is clearly defined and is more than vapour or smoke.
The ability to cast a corporeal or non-corporeal Patronus is down to the skill of the witch or wizard. Each Patronus is unique to the witch or wizard who conjures it, and it’s possible, in some cases, for a Patronus to change.

In The Tales of Beedle the Bard, the author presented his own version of the origin of the Hallows. Hundreds of years ago, the three Peverell brothers were travelling at twilight, and reached a river too dangerous to cross. The three brothers, being trained in the magical arts, simply waved their wands and created a bridge across the river. They were then stopped by Death himself, who felt cheated that they had gotten across the river, as most travellers drowned in it.
Death, a cunning liar, then pretended to congratulate them on being clever enough to evade him, and offered each of them a powerful magical item. The first brother, Antioch Peverell, wished to have the most powerful wand out of his combative personality; Death broke a branch off a nearby elder tree and created for him the Elder Wand, a wand more powerful than any other in existence. The second brother, Cadmus Peverell, out of arrogance, wanted to humiliate Death even further, and wished to have the power to bring loved ones from the grave; Death then took a stone from the riverbed and created for him the Resurrection Stone, a stone capable of bringing the dead back to the living world. The third brother, Ignotus Peverell, who was a humble man, did not trust Death and asked to go on from the river without being followed by Death; Death then gave him his own Cloak of Invisibility, an invisibility cloak that never lost its power through curses or age. In time, the brothers went their separate ways.
The three legendary objects, (the cloak, the wand and the stone) together made up the Deathly Hallows.
Instead of being rewards for their cleverness, the Deathly Hallows were actually part of a cunning plan by Death to kill off the Peverells so he could take them for his own. However, Albus Dumbledore felt that it was more likely that the Hallows were actually created by the very talented and powerful brothers, and that the story of their origins as objects fashioned by Death sprang up around them as result of the powers they possessed.
Antioch travelled to a wizarding village where he killed the man he once duelled with, he then boasted of the power of the Elder Wand, that it was unbeatable and in his possession, invoking envy amongst the many wanting to possess it for themselves. His throat was slit in his sleep by another wizard who stole the Elder Wand.
Cadmus travelled back home and used the Resurrection Stone to bring back the woman he loved, but was dismayed to find that it was only a pale imitation of her: the dead did not belong in the living world and could not truly be brought back. He found that she was cold, lifeless, and miserable in the land of the living, nothing like she used to be. In the end Cadmus committed suicide by hanging himself so he could truly join her.
Ignotus used the cloak to remain hidden from Death for a long time. When he was an old man, he passed the cloak onto his son, greeted Death as an old friend, and went with him to the next world.
That is a children's tale, told to amuse rather than to instruct. Those of us who understand these matters, however, recognise that the ancient story refers to three objects, or Hallows, which, if united, will make the possessor Master of Death.