Avada Kedavra cannot be blocked as you correctly pointed out, except by physical objects as seen when Dumbledore duels Voldemort in the Order of The Phoenix, or due to the effects of Priori Incantatem as a result of wands with twin cores duelling as explained in Goblet of Fire.
Voldemort cast the Killing Curse and Harry cast the Disarming Charm, and because their wands had twin cores, Priori Incantatem occurred; Harry was not killed and was able to hold Voldemort off to give him time to escape.
The Killing Curse is a spell that causes instantaneous death and is one of the three Unforgivable Curses. Its incantation is Avada Kedavra. The only known counter-spell is sacrificial protection, which uses the magic of love. However, one may dodge the green bolt or block it with a physical barrier.
Voldemort's signature spell was Avada Kedavra. Harry's was Expelliarmus.
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.
Speak to Sebastian in the Undercroft after this and he'll teach you any Unforgivable Curses you have missed up to that point, including Avada Kedavra. It's worth learning the curse as doing so should have no negative outcome on the game's story.
1 Avada Kedavra Is Just Ridiculous
Only love itself, the strongest magic of all, can block the Killing Curse. Lord Voldemort cast this spell constantly in his lifetime, and it's the spell that killed Harry's parents in particular.
According to records from the wizarding world, he is thought to have been among the most powerful wizards in human history. Merlin attended Hogwarts as a Slytherin and displayed a remarkable command of the magical arts. Some claim that he is the most potent wizard ever.
Phoenixes were semi-protected from the Killing Curse, due to them being immortal. In 1996, Fawkes swallowed one intended for Albus Dumbledore, causing him to burst into flame and die instantly. However, he then was reborn from his ashes. This makes phoenixes resistant to the Killing Curse.
Her sacrifice gave Harry the power of love, a protection spell sealed with the blood spilled by her death.
Harry used Expelliarmus , a disarming spell, on Voldemort in the final battle because Harry was never going to cast a killing curse on someone, even Voldemort.
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.
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.
Exactly. Harry's spell simply rebounded a weak killing curse back onto Voldemort who was extremely weakened with all of his Horcrux's destroyed. The Elder wand couldn't conjure a full power curse for Voldemort. Especially against its master.
As for everyone's favourite child-bullying adult, Snape's Killing Curse was 'blue' due to the cyanish background of the film scene. It was actually green, but the camera and effects made a bluish overlay which overlapped the green spell.
MERLIN. Probably the most famous wizard in all of popular culture—yes, even eclipsing Harry Potter—Merlin's greatest feat was helping Arthur Pendragon find a very nice sword (Excalibur) and an even nicer cup (the Holy Grail).
Avada Kedavra
It's used to kill people, it's an Unforgivable Curse, and it was Voldemort's favourite, so it's going last.
So, of course, whenever they find themselves facing each other one-on-one, he is throwing the killing curse (Avada Kedavra) Harry's way. Not many characters in this series have been bold enough to cast the killing curse like Voldemort is, and it is without a doubt, his favorite spell.
Firestorm. Firestorm was a spell that created a large ring of fire around the caster's wand. This spell is one of the last and most powerful spells that Albus Dumbledore cast using the elder wand before his death.
When Sebastian questions his actions, with “If I hadn't known how to cast it-”, you will have to respond with either of the two following options- “No one should know that curse.” and “Everyone should know that curse.” Choose the latter, after which Sebastian will offer to teach it to you.
Overview. 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.
Aveda Kedavra has one effect: it kills. Other curses can be just as lethal. The only clear canon instance of a good wizard using Avada Kedavra to kill is Snape's euthanasia of Dumbledore.