Jason Isaacs, who plays Lucius Malfoy in the Harry Potter movies, recently expressed how proud he was of his once on-screen son, Tom Felton in a moving Instagram post that praised Felton's acting skills in the play 2:22 A Ghost Story - which premiered this September. Isaac's heartwarming words reminded everyone of the incredible roles the actors achieved in Harry Potter and how iconic they were as a pair.
The Malfoys were crucial characters of the franchise and their alliance with Death Eaters made them witness the Killing Curse more than a couple of times. In spite of being one of the three unforgivable curses, Avada Kedavra is not the only spell that can kill someone, and there are plenty that could be used to end anyone's life.
Disintegration Spell
Molly Weasley made everyone's jaw drop when she defeated the powerful Bellatrix Lestrange by casting a spell that disintegrated her into dust. As fans remember, Molly didn't pronounce any words that would suggest the use of a specific spell, but she appeared to cast a deathly combination of them.
Not all spells have to be named, and the most skilled wizards can cast them without saying a word. Molly appeared to have used the hardening charm, Duro, or the freezing charm, Inmobulus, to then throw a disintegration spell that finally killed Bellatrix, which most fans agree, was quite brilliant.
Repello Inimicum
The spell is usually mixed with Protego Maxima and Fiantu Duri and it disintegrates anyone who enters the barriers created by the charm. It was used in the Battle of Hogwarts to protect the castle, but one of the worst things that happened to Hogwarts professors was that Death Eaters were able to destroy it.
However, its deathly effects on anyone who passes the barrier are so well known that Voldemort's followers refused to try to get into Hogwarts until the shield had vanished. They all knew that a simple touch could end their lives.
Bombarda
Bombarda creates a small explosion that can become quite useful, as Hermione proved when she made one of her best decisions in The Prisoner of Azkaban and used the spell to open Sirius Black's cell and free him. The stronger version of the spell, bombarda maxima, provokes an even bigger explosion, and Umbridge showed its destructive attributes in Hogwarts.
Although in the franchise, the spell was only used for opening doors or breaking down walls, explosions can be quite dangerous and deathly if used with that intention. Luckily, wizards usually resort to other less gruesome techniques to harm others.
Confrigo
Hermione used this spell when she tried to protect Harry and herself from one of Voldemort's most evil Horcruxes, Nagini, in Godric's Hollow. The spell produces a fiery explosion that can cause severe injury or death.
Consequently, Hermione used it in an attempt to kill Nagini, although she failed. However, the image of Nagini squirming after receiving the curse proves how powerful the spell really is, and how used on someone that is not a Horcrux, can be lethal.
Evanesco
When Hogwart's students were taught about this spell, Minerva McGonagall explained that inanimate objects and living things that vanished because of it turned "into non-being, which is to say, everything."
Professor McGonagall's explanation sounds like a metaphor for death, although explicitly, the spell does not kill. However, it can make anyone become non-being, nonexistent, which can have very similar and devastating consequences for the animal or person on whom the spell is inflicted.
Piertotum Locomotor
Minerva McGonagall used this spell to activate Hogwart's soldier statues that defended the castle in the Battle of Hogwarts and followed up with a quote that proves McGonagall is the best wizard: "I've always wanted to use that spell."
The spell can be used to animate objects and control or command them, which is quite useful if there's a need to defend a school from evil Death Eaters and other creatures. As Professor McGonagall showed, if said objects are commanded to kill, they will. Which is exactly what the Hogwart's statues did.
Oppugno
The Oppugno charm directed objects or living things to attack a target. The jinx has many uses, and it can be as harmless as it can be deathly. Harry used it in the Ministry of Magic to distract everyone with violent papers, Hermione to attack Ron with canaries, and Minerva used it to defend herself from Death Eaters.
The devastating effect of the spell depends on the objects or beings that are jinxed. Papers can leave a few cuts, and Canaries a few bites, but if the spell is cast on daggers, rocks, or more violent animals, the target's destiny can be truly catastrophic.
Protego Diabolica
Protego Diabolica is a powerful dark charm that creates a protective ring of black fire that incinerates enemies but leaves allies untouched. Audiences witnessed its devastating effects for the first time in Fantastic Beasts: The Crimes of Winderwald, as Grindelwald himself cast it around him.
Another property of the spell that makes it even deadlier is that the flames produced can be moved by the caster, which means that the circle's extension can grow in any direction. The lethal spell can prove useful to the most bloodthirsty individuals, and it is powerfully scary.
Sectumsempra
Harry Potter was horrified when he cast this curse upon Malfoy, just like every reader and viewer witnessing the scene. Sectumsempra cuts the flesh of the individual which is cast upon and provokes a gruesome and bloody sight that is difficult to watch.
It could even be considered crueler than the Killing Curse, given that it causes an extraordinarily painful and slow death. If it wasn't for Snape, Draco would have died in a horrendous way that nobody deserves.
Fiendfyre
Fiendfyre is a powerful curse that many wizards know to not take lightly, except for Crabbe of course, who underestimated it and died eaten by its fiery spell. The incantation creates wild flames that shape into different creatures that kill everything that's in their way.
Given that it consumes everything on its path, it is safe to say that it is one of the deadliest spells that exist in the Harry Potter universe, but its biggest disadvantage is that it soon grows out of control, and endangers everyone, including its caster.