The three curses that are classified as Unforgivable are the Imperius Curse, the Cruciatus Curse, and the Killing Curse.
Avada Kedavra, also known as the Killing Curse, kills a person instantaneously and without injury. There is few counter for it, and only one person, Harry Potter, has ever survived it with Sacrificial Protection that has been endowed upon Harry Potter by His Mother Love for Him.
Therefore, figuring out a spell that is Draco's favorite is hard and, in the movies, there is no defining moment that cements a spell as his favorite. Based on Harry Potter lore, and an article by The Healthy Journal, Draco's signature spell is a N.E.W.T standard spell, The Protean Charm.
Avada Kedavra
It's used to kill people, it's an Unforgivable Curse, and it was Voldemort's favourite, so it's going last.
In the movie, Hermione whispers "Obliviate," which makes it clear that she is casting this spell. The Obliviate spell is one of the most memorable from Harry Potter.
The Fidelius Charm is extremely ancient and still used to this day. It involves the concealment of information inside a living person. The chosen person, or Secret Keeper, is the only person who is thenceforth capable of revealing the protected information to others, however many previously knew it.
The Elder Wand is one of the most sought-after objects in the Harry Potter universe. Unlike other wands, this particular prop had the distinction of passing hands from two major characters: Voldemort (Ralph Fiennes) and Harry himself (Daniel Radcliffe).
The darkest of the Dark Arts, Harry Potter unforgivable curses are the Cruciatus Curse, the Imperius Curse, and the Killing Curse. Although the curses are highly illegal, Harry using Unforgivable Curses happened, but he uses them once he was thrust into the Second Wizarding War.
The three Unforgivable Curses are the Cruciatus Curse, which causes unbearable pain; the Imperius Curse, which allows the user to control the actions of the victim; and the Killing Curse, which causes instant death.
Harry became so enamoured with the spell that he eventually used it to finish off Lord Voldemort. Here's how Harry's relationship with Expelliarmus became his signature – and why that's a good and bad thing.
They are the Killing Curse, Avada Kedavra, the Cruciatus Curse, Crucio, and the Imperius Curse, Imperio.
I've always suspected Molly's lethal spell was a particularly well-placed and powerful stunner that stops Bellatrix's heart, which is consistent with the description of her death: Molly's curse soared beneath Bellatrix's outstretched arm and hit her squarely in the chest, directly over her heart.
Using the highly advanced art of spell creation, Voldemort was able to create four spells/magical items unique to him alone. These included being able to fly under his own power, creating the infamous drink of despair, the rudimentary body potion, and morsmordre.
Silencio is used to silence an object or a person.
Expulsion was never seen in the movies, but a very similar spell known as Bombarda Maxima was. It is the most powerful form of explosive enchantment, that causes large explosions powerful enough to tear down walls.
History Of Avada Kedavra
The Killing Curse was created in the early Middle Ages by Dark witches and wizards. Primarily, the curse was used to quickly slay opponents during a duel.
Ginny and the Bat Bogey Hex
As the youngest Weasley, we're sure Ginny observed more than her fair share of unpleasant spells over the years but it was the Bat Bogey Hex she was famous for – and with good reason.
Hermione's bluebell flames
Hermione first uses it against Snape when she and Ron think he is cursing Harry's broom in his first Quidditch match. Her bright blue flames set Snape's robes alight, before Hermione scoops them up and puts them into a jar.
In Deathly Hallows, Hermione faced a real test of her physical and psychological stamina. After being on the run from a bunch of Snatchers, the gang were taken to Malfoy Manor, where Bellatrix proceeded to torture Hermione using the Cruciatus Curse.
Other Favorite Spells
Plus, there were some votes for Obliviate (erases memory), Silencio (silences someone or something), Homonculus Charm (reveals someone's true identity and location), and Levioso (levitation, and some fans say that this is Ron Weasley's signature spell).
Voldemort's greatest fear is death and as a result a boggart takes the form of his own corpse. It is unsurprising that this is Voldemort's biggest fear. After all, he did split his soul up encasing it in various horcruxes just so to keep himself from dying.
In Harry Potter And The Deathly Hallows Part 2, Voldemort kills Snape using his snake Nagini instead of his favorite spell Avada Kedavra - here's why. Voldemort killed Snape in Harry Potter And The Deathly Hallows Part 2 using his Horcrux snake Nagini instead of his favorite Unforgivable Curse, Avada Kedavra.