The Deathly Hallows from Harry Potter are among the most mysterious forms of magic that Harry came across, but their individual powers might be explained by the equally mysterious Thestrals. The winged beasts are often associated with death and are feared despite their gentle nature. Similarly, the Hallows are supposed to make the person who reunites them the Master of Death. However, they, too, are highly misunderstood in the world of Harry Potter - and their connections don't end there.
Harry first learned about the Deathly Hallows in Harry Potter and the Deathly Hallows, and they played a significant part in his destiny at the end of The Deathly Hallows Part 2. The legend of the Three Brothers detail how three men made a deal with Death to acquire these three items: the Cloak of Invisibility, the Elder Wand, and the Resurrection Stone. Each item was meant to cheat death, but wizarding adventurers have long suspected they were created by three talented individuals known as the Peverell brothers. The fact that Harry is descended from the Peverells proves this to be true - but it's still unclear how they were made.
Harry Potter Theory - The Peverell Brothers Were Experts On Thestrals
Though the Harry Potter series never revealed how the power of the Deathly Hallows was possible, there are striking similarities between their properties and that of Thestrals. Witches and wizards often avoid these magical creatures since their association with death can be offputting. However, since the legend of the Peverell brothers makes it clear that they did not fear Death and were said to have 'conquered' him instead, it could just be that they were experts on the wildly misunderstood Thestrals.
The character of Death is certainly mysterious in The Deathly Hallows, but since Harry saw no such person when he turned up in the King's Cross purgatory, it can be assumed that he isn't a literal being. Instead, the Peverells likely researched Thestrals, and much like other magical beasts are used to make powerful objects, the Death-like horses provided 'gifts' that they used to create the Hallows. Over time, their story became a legend, and the more logical details gave way to a tale of deadly bargains.
The Elder Wand Has A Thestral Core In Harry Potter
The Deathly Hallows' most apparent connection to Thestrals is the Elder Wand. It gets its name because it is made of the wood of an Elder tree, which has long been believed to be unlucky in Harry Potter's wizarding world. However, what truly made the Death Stick special was its core - the hair of a Thestral. Wand lore states that the Elder Wand wasn't the first occurrence of a Thestral hair core, but they are unpredictable and difficult to control. Somehow, the Peverelle brothers, specifically Antioch Peverell, must have found a way to stabilize his.
The Elder Wand is supposed to be unbeatable, though there seem to have been instances (such as the duel between Grindelwald and Dumbledore) that this turned out untrue. Regardless, the wand clearly has unique power. In the Harry Potter books, Antioch's Hallow was the only known way to fully repair a previously broken wand - though this was retconned in the Deathly Hallows Part 2 movie. Whether the wand's impossible abilities can be attributed to Thestrals is unclear - but the beasts are certainly involved.
The Invisibility Cloak Is Made From A Thestral's Coat
After the Elder Wand, the Deathly Hallows' connection to Thestrals becomes much more speculative. Still, the Cloak of Invisibility and Thestrals have one clear thing in common - they can be entirely invisible. Until someone sees death firsthand, they won't be able to see a Thestral. Harry went several years believing that the school's carriages pulled themselves, only to see them in Harry Potter and the Order of the Phoenix after he had watched Cedric Diggory die. Coincidentally, this magic might have been exactly the same as what allowed his inherited Invisibility Cloak to work.
Harry's Invisibility Cloak wasn't the only one in existence in the wizarding world, but it was the most powerful. Standard cloaks that grant invisibility would be either enchanted with a spell or made from the coat of a Demiguise - magical creatures who can also become invisible (though not entirely imperceptible). This indicates that making a cloak of a Thestral would have a similar effect. Of course, Harry's cloak made him invisible even to those who witnessed death. Still, it's possible that Ignotus Peverell's expertise on Thestrals allowed him to work around this.
The Resurrection Stone Comes From The Eye Of A Thestral
The Resurrection Stone is likely the most mysterious of the Deathly Hallows. In actuality, it doesn't bring the dead back to life. Instead, it allows the user to peer through the veil of death and see their deceased loved ones around them. Harry experienced this in Harry Potter and the Deathly Hallows when he prepared to walk to his death. His parents, Lupin, and Sirius appeared to usher him onward and revealed that they had never truly left him. The Stone had simply allowed him to see what was already there.
For this reason, the Deathly Hallows Thestral theory becomes a little unclear regarding the Resurrection Stone. However, if Thestrals could see the dead and be seen by those who had experienced death, it could line up. If this were the case, the Stone might actually be the lens from the inside of a Thestral's eye. If Cadmus Peverell found a way to turn the rough, black stone into a usable item, it makes sense that it would reveal the world that the Thestrals see. Of course, if the user wasn't ready to join them, it's easy to think that this sight would drive them mad, as the Harry Potter books say.
The Deathly Hallows Don’t Really Make Someone Master Of Death In Harry Potter
Of course, if the Deathly Hallows from Harry Potter were made using the magic of Thestrals instead of having been fashioned by Death himself, then the legend would also be wrong about what happens when combined. When Harry walked into the Forbidden Forest under his Invisibility Cloak, holding the Resurrection Stone, and with the loyalty of the Elder Wand, he had technically combined them (as confirmed by Dumbledore in the King's Cross purgatory). However, his blood in Voldemort's veins kept him alive, not the Hallows.
Ultimately, the Deathly Hallows were simply powerful items made by powerful wizards - potentially with the help of some powerful magical beasts. Thestrals have a strange connection to death that the wizarding world in Harry Potter doesn't fully understand. If the Peverell brothers could harness this power, it's logical that those around them would consider them to have mastered death. In the end, the legend turned out to be more prophetic. Harry was the Master of Death since he had defied it three times, so he was therefore destined to reunite the Thestral-inspired Hallows.