Weak: Quirinus Quirrell Although he was intelligent and bookish, Quirinus Quirrell was the weakest of the Hogwarts professors—mostly due to his extremely timid nature. He taught the Muggle Studies course for several years before going in search of the vanquished Voldemort.
Peter Pettigrew
Though he is accomplished in some ways, he is arguably one of the weakest wizards. Through his time in school he is described as latching on to Remus Lupin, Sirius Black and James Potter as stronger wizards he believed could protect him.
Formerly known as Tom Marvolo Riddle, Lord Voldemort was the most formidable evil wizard in the entire universe. Until Harry Potter, Voldemort's magical prowess was practically unmatched, and no one could stand a chance against him.
Godrick Gryffindor, one of the four founders of Hogwarts, and the owner of the legendary Sword of Gryffindor, was absolutely more powerful than Dumbledore— and it's a good thing he was, too, because Dumbledore wasn't around in Hogwarts' early days to keep Godrick's fellow founder Salazar Slytherin in check.
12 More Powerful: Severus Snape
He was the Half-Blood Prince, as well as the maker of several powerful spells. Severus Snape might have pretended to serve Voldemort (while in fact, as we all know, working as a double agent for Dumbledore), but there's almost no question he was more powerful than the Dark Lord.
Strong: Severus Snape
As a potions master, Snape possessed astounding skills—effortlessly brewing the most difficult potions and even improving upon their recipes. He demonstrated those masterful abilities when he invented a potion and incantation that saved Dumbledore's life after he encountered Voldemort's curse.
1. Albus Dumbledore. Image via Warner Bros.
In recent history, two Dark wizards of particular notoriety were Gellert Grindelwald and Lord Voldemort. Both were considered the most powerful Dark wizards of their time, with Voldemort considered to be the most powerful Dark wizard of all time.
Even though there are only a few examples of wizards who never strayed to the path of evil or found a way to redeem themselves, it should be enough to solidify that not everyone in Slytherin is evil. Like I mentioned before, other houses have spawned other evil and treacherous wizards.
Elder. The rarest wand wood of all, and reputed to be deeply unlucky, the elder wand is trickier to master than any other. It contains powerful magic, but scorns to remain with any owner who is not the superior of his or her company; it takes a remarkable wizard to keep the elder wand for any length of time.
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.
Nobody can deny that Hermione Granger is the smartest character in Harry Potter, gender notwithstanding. She is consistently the best student in every year, earning extraordinary marks in all her exams and ten OWLS.
In each installment of the Harry Potter series, Hermione Granger is the smartest of the trio. She has the best academic memory, highest grades, and always expanding her knowledge. However, it is Hermione's logic and by-the-book mentality that allows Harry to surpass her.
It shouldn't be hard to believe, but Draco Malfoy was the second most intelligent student in all of Harry's year. That Slytherin determination can accomplish quite a lot. Draco received at least three OWLs (including both Transfiguration and Potions) and he is very competitive with Hermione.
Belonging to the Black family, Phineas is one of Slytherin's loveliest members. Taking a greater moral standpoint than his other family members, who mostly believe in pure-blood supremacy, this good-natured wizard has shown himself to be an especially well-behaved member of the otherwise unruly Hogwarts house.
1. Voldemort. Tom Riddle took the core qualities of Slytherin to new heights, as he became arguably the most powerful dark wizard of all time. He learned how to split his soul and create numerous Horcruxes, thereby making himself immortal as long as the Horcruxes existed.
The Head of Slytherin is Horace Slughorn (who left the role to Severus Snape for fifteen years before taking it up again in 1996) and the House's patron ghost is the Bloody Baron.
Voldemort summons Snape to the Shrieking Shack. Erroneously believing Snape is the master of the Elder Wand and that Snape's death will make him the master of the Wand, Voldemort kills Snape by having his pet snake Nagini bite him through the neck.
So in summary, Snape is so angry with Harry in particular because he is petty in a sense; punishing the son for the sins of a father he never knew. He's ferocious with the other houses and is only nice to his Slytherins because he needs to preserve his role as a spy.
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.