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.
If you get hit by Avada Kedavra, you die. If you try to put anything in front of it that isn't a solid object (like a spell), you die. The only reason Harry survived when he used Expelliarmus against Voldemort's Killing Curses was due to extenuating circumstances.
Harry makes use of two of the Unforgivable Curses in the books. Dueling with Bellatrix Lestrange, he attempts the Cruciatus curse, with limited results; Bellatrix says that he has to really hate someone to make the Unforgivable Curses work properly, righteous indignation isn't enough.
By contrast, he's never used Avada Kedavra, far less in a combat situation. His other uses of Unforgivable Curses have had mixed results: although he used the Imperius curse successfully while breaking into Gringotts, his initial attempts to use the Cruciatus curse on Bellatrix and Snape were unsuccessful.
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.
Voldemort intentionally made six Horcruxes, but when he used Avada Kedavra on Harry, he unintentionally created a seventh Horcrux. Instead of dying, Lily's love for Harry created a counter 'curse' known as Sacrificial Protection and saved Harry.
Cruciatus Curse ('Crucio')
Harry tried to use this spell himself. The first time was against Bellatrix after she had killed Sirius. His attempt was unsuccessful because, as Bellatrix mockingly explained: 'You need to really want to cause pain – to enjoy it – righteous anger won't hurt me for long…'
None of the good guys dare use the Killing Curse throughout the events of the movies and books, no matter how high the stakes and how difficult things are. But Ron Weasley is the exception, giving it a go in the Deathly Hallows: Part 2 movie when himself and Hermione look destined to die via Nagini.
They are the Killing Curse, Avada Kedavra, the Cruciatus Curse, Crucio, and the Imperius Curse, Imperio.
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.
In conclusion, we don't see Dumbledore perform an Unforgivable in canon. He probably never performed the Imperius or Cruciatus Curses. He probably did kill at least once, but only when he had no other alternative.
Harry survived two direct attacks: once in 1981 after his mother's self-sacrificing love protected him from Lord Voldemort, and once in 1998 after the curse, cast again by Voldemort, failed to kill Harry, as he was tethered to life by Voldemort himself, due to Lily's blood protection which he took inside himself during ...
Avada Kedavra
Topping the list for the most powerful spells in the Harry Potter universe is no other than Avada Kedavra, Voldemort's favorite to instill his will and fear onto others. The spell itself is a play on Abra Kadabra and is easy to cast by just about anyone in the Wizarding World.
The Avada Kedavra – the killing curse from the Harry Potter Wizarding World is unforgivable, cannot be blocked, and is colored green.
There is likely a good reason that the Sectumsempra is not an unforgivable curse. It's mostly because Sectumsempra is Snape's personal curse that he created. It is not a widely known or used spell, and it is one that he kept secret — which means it can't be added to the list since no one really knows about it.
Draco Malfoy (Cruciatus and Imperius Curses)
He's never seen using the Killing Curse, but under strict orders from Voldemort, he's known to have used the other two.
that it was the killing curse that ron used he just didn't have it in him to use the spell to its full. effect. he didn't know how to use it or what it meant to use it. and that's why it failed.
He was a curse-breaker for Gringotts
Not only did Bill have goblins for colleagues – notoriously tricky customers – but he also got to do the majority of his work amid the pyramids of Egypt. He was pretty much the closest the wizarding world had to Indiana Jones.
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.
In the film Harry Potter and the Deathly Hallows: Part 2, this duel has some noticeable differences: In the film, Bellatrix casts a blue spell at Ginny Weasley instead of a Killing Curse, who deflects it using a Shield Charm.
As much as Bellatrix loves Lord Voldemort, she equally hates Harry Potter, considering him the greatest threat to Voldemort and his plans. She will do anything to assist the Dark Lord's desire to defeat Harry.
Her sacrifice gave Harry the power of love, a protection spell sealed with the blood spilled by her death.
Draco Malfoy's mother Narcissa was cold, cunning and devoted to the Dark Lord. But she was also a mother, which meant she was willing to risk everything to make sure her son was safe. When Harry survived Voldemort's Killing Curse for the second time, Narcissa pretended he was dead so she could get to Draco.
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).
Riddikulus
Riddikulus is the spell that's used when facing a Boggart, and it's used to turn the Boggart into something that the caster finds funny.