Quirinus Quirrell

"I met him when I traveled around the world. A foolish young man I was then, full of ridiculous ideas about good and evil. Lord Voldemort showed me how wrong I was. There is no good and evil, there is only power, and those too weak to seek it."

- Professor Quirrell talking to Harry Potter about Lord Voldemort. "No dear boy. I tried to kill you! And trust me, if Snape's cloak hadn't caught fire and broken my eye contact, I would have succeeded! Even with Snape muttering his little counter curse."

- Professor Quirrell revealing his true colors.

Professor Quirinus Quirrell is the main antagonist of Harry Potter and the Philosopher's Stone. He was a half-blood wizard and the Muggle Studies professor at Hogwarts. He became the Defense Against the Dark Arts teacher during Harry Potter's first year at Hogwarts. Although Severus Snape was initially thought to be the one trying to steal the Philosopher's Stone, it is ultimately revealed that the real villain is Quirrell, who is a dark wizard working for Voldemort.

He was portrayed by Ian Hart, who also did the voice of Voldemort in the same film.

Early life
Quirinus Quirrell was born on September 26, 1972, or earlier, somewhere in the British Isles, to one Muggle (non-magical) parent and a witch or wizard, and was considered very gifted and delicate as a child. When he started at Hogwarts School of Witchcraft and Wizardry, he was sorted into Ravenclaw due to his brilliant mind, but was teased for his timidity and nerves during his school life. Feeling inadequate and wishing to prove himself, he developed an (initially theoretical) interest in the Dark Arts, hoping to gain undesirable power that would help him pick himself up. These feelings of worthlessness that this bullying fostered embittered the boy, forging a latent desire to make the world sit up and notice him.

Following his graduation from Hogwarts, Quirrell most likely obtained a high-graded O.W.L. and N.E.W.T. in Muggle Studies and Defence Against the Dark Arts, since not only did he go on to teach both but was also noted to have had a gift for the theory of Defensive Magic. Quirrell was excellent at magical theory, but when it came to practice he was an average wizard. His gift was his brilliant mind rather than his strength.

After teaching Muggle Studies at Hogwarts for some time, he took a year-long travel around the world in 1990 to get subject for his lessons in the Dark Arts, claiming it was a sabbatical he was taking in order to "gain first-hand experience". In reality, Quirrell's reason for this world tour was to find whatever remained of one of the most powerful (and immortal) psychopathic dark wizards of the century, Lord Voldemort, who met his defeat nine years back at the hands of Harry Potter (who was then a year old at the time), partly out of curiosity and the unacknowledged desire for importance from his childhood. At the very least, Quirrell fantasised that he could be the man who tracked Voldemort down, proved successful when he found the disembodied dark wizard in a forest in Albania but was no match for him (even in such a weakened state). When Voldemort realized that Quirrell had a position at Hogwarts, he used his charisma to manipulate the young teacher into joining his cause.

From then on, the shy, young Quirrell became much more confident and ruthless, but kept acting like his old self as a facade. He kept up the pretense of stuttering and twitching his body, but this was all a facade. Under the apparent shyness and nervousness of the young professor was in fact a ruthless monster, circling the young Harry like a shark about to strike. The real Quirrell became cold, ambitious, cruel and arrogant, and had mastered high levels of dark magic from Voldemort - such as flight, Occlumency, Legilimency, and conjuration - yet he kept these levels of magic hidden from the body of Hogwarts. Quirrell generally got along well with most of Hogwarts' faculty and they considered him to be a very clever and talented wizard for his world travels and experiences with the dark arts. After his travels, Quirrell started exaggerating his old personality as a facade, faking a prominent stutter when speaking and excessive paranoia and timid behavior. This caused Albus Dumbledore's suspicions.

Harry Potter and the Philosopher's Stone
Quirrell spends most of this year trying to steal Nicolas Flamel's Philosopher's Stone for Voldemort. Flamel and Dumbledore felt that the stone was too dangerous even at Gringotts Wizarding Bank, especially with the bodiless Voldemort lurking around. The two agreed to change the stone's location to Hogwarts, closer to Flamel's old friend Dumbledore, the only person Voldemort ever feared.

During the last weeks of summer, Quirrell goes to Diagon Alley, preparing to steal the Philosopher's Stone for Voldemort. When Harry Potter and Rubeus Hagrid are about to visit Diagon Alley to buy Harry's equipment for Hogwarts they enter the Leaky Cauldron. In the Leaky Cauldron, Harry is recognized by many witches and wizards, who are delighted to see the Boy Who Lived and want to shake his hand. There, Hagrid introduces Harry to Quirrell and the two shake hands. Quirrell pretends that he is going to buy a new book on vampires at Diagon Alley. After a short conversation, in which Harry notices Quirrell's distinctive stutter, Quirrell leaves them and Harry and Hagrid enter Diagon Alley. In the movie adaptation Quirrell is already wearing a turban, unlike the book, and does not shake Harry's hand.

Unbeknownst to Harry and Hagrid, Quirrell breaks into Gringotts, the Wizarding Bank, the same day and attempts to steal the Philosopher's Stone, but the vault was emptied by Hagrid only hours before on Dumbledore's orders. This leads Voldemort to the decision that he needs to watch Quirrell more closely and he decides to possess Quirrell's body. To hide Voldemort's face, which is now growing out of the back of his head, Quirrell wears a purple turban for everyday to use; Voldemort's presence results in a foul stench to emanate from it. Quirrell claims to have received it from an African prince as compensation for disposing of a zombie. Students, including Harry, notice the smell but, as Quirrell claimed to have a backstory with a vengeful vampire from a travel in a vampire community in Albania's Black Forest, believe that the turban is simply filled with garlic. Quirrell also reportedly had nasty bit of trouble with a hag. Sometimes Quirrell tries to put up feeble resistance against Voldemort's possession, but the dark lord is far too powerful for him. Voldemort uses Legilimency on Quirrell's mind, often to punish him.

When the Philosopher's Stone is hidden at Hogwarts many teachers are asked by Dumbledore to help protect it, including Quirrell. Quirrell, who has a hand with trolls, dispatches one especially huge and nasty specimen to guard the stone. As no teacher knows what spells protect the stone except their own, this goes unnoticed.

At Hogwarts, Quirrell teaches Defence Against the Dark Arts, while another wizard replaces him as Muggle Studies professor. During the Sorting Ceremony, Harry recognizes him, despite the huge turban. The majority of the students find Quirrell's lessons to be a joke, as he was not very good in the application of his knowledge to the students. Quirrell uses his nervous and timid disposition to his advantage and acts like a poor wizard with no talent, as his perceived lack of confidence had earned very little respect from the students at Hogwarts and consequently diverts suspicion away from his plans. Only Dumbledore notices Quirrell's sudden exaggeration of his old personality and Professor Severus Snape also noticed with suspicion Harry pressing his scar in slight pain while the two stared at each other near Quirrell, while his head was turned towards Snape. Dumbledore tells Snape to keep an eye on Quirrell.

Quirrell does not act until Halloween, where he unleashes a mountain troll in Hogwarts to cause a distraction. Planning to steal the Philosopher's Stone while the rest of Hogwarts' staff is dealing with the troll, Quirrell pretends to faint and once everyone leaves the Great Hall, he sneaks to the restricted Third Floor Corridor where the Stone is being hidden. However, Quirrell is instead stopped when Professor Snape, who grew suspicious of him, arrives first to prevent anyone from trying to steal the stone. However, the Cerberus Fluffy, one of the Stone's guardians given by Hagrid, bites Snape and injures his leg, while the latter was trying to send Quirrell away. Acting like nothing happened, both teachers catch up with the rest of the staff and they arrive to see that Ron Weasley and Harry Potter defeated the troll. There, Quirrell stays behind with the unconscious troll until the beast groans, scaring Quirrell.

Not clear to anyone how Harry could have been able to defeat Voldemort and survive the killing curse, Quirrell feels that the boy is too dangerous to stay alive, especially after seeing him defeating a troll at young age, and decides he must dispose of him soon, while he is still young and knows little of magic. Quirrell makes his first attempt at Harry's life in November, during the first Quidditch match of the season between Gryffindor and Slytherin, Quirrell bewitches Harry's broom with a jinx, causing it to buckle and to try to throw Harry off to his death. Snape interfers again and begins to utter a counter-curse in order to save Harry. However, Quirrell is succeeding anyway and Harry goes close to fall. When Hermione Granger, believing that Snape is the one who is trying to kill Harry, sets fire to Snape's robes to distract him, she accidentally knocks over Quirrell in her hurry to reach Snape, and thereby disrupts Quirrell's concentration, causing him to break the eye contact necessary for performing his spell correctly. In the movie adaptation, Snape knocks Quirrell over while trying to put out the flames.

In December, during Christmas holidays, Fred and George Weasley get to trouble for bewitching snowballs that follow Quirrell around wherever he goes and hit the back of his turban. With most students away from Hogwarts on their Christmas holidays, the school is half-empty, but Quirrell keeps a low profile from Dumbledore and tries to figure out a way to deceive the ferocius Fluffy, who is impossible to tame.

In January or February, on his way back from his victory during the Quiddtch match between Gryffindor and Hufflepuff, Harry finds Snape and Quirrell in an intense exchange. Snape is facing Quirrell over the latter's loyalties, however from Harry's point of view it seems as though Snape is trying to intimidate Quirrell into helping him steal the Philosopher's Stone. Before this, Harry had no idea of what could be possibly guarded by Fluffy and this is the first time he hears about the object, much to realization. Snape asks Quirrell if he has found a way to finally steal the Stone and angrily mentions spells hard to surpass, giving Harry the imperssion that Snape is forcing Quirrell to help him. Sensing that someone is near, Snape stops intimidating Quirrell (who is only pretending to be scared), instead telling him that they will have a little chat soon enough when Quirrell had enough time to decide where his loyalties lie. In the movie adaption this conversation takes place earlier, still during Christmas' holidays, right after December 25, in the night, when Harry was sneaking in the library's Restricted Section. Snape and Quirrell are also alerted by Argus Filch, who tells them that he found Harry's lamp in the library. The two teachers and Filch then go to search for students sneaking around.

Harry tells Ron and Hermione about Snape and Quirrell's meeting. After finding out about Nicolas Flamel's historical and notorious identity and reading about the legendary Philosopher's Stone, the three realize that the Philosopher's Stone is indeed protected by other things, besides Fluffy. Convinced by Hermione, Hagrid confirms this to them, and the three believe that Snape has found a way to get past all of the other teachers' spells, except Quirrell's and of course Hagrid's protection, Fluffy. They assume that Snape is using intimidation trying to break Quirrell into telling him the way to pass his defenses, thus helping with treason and theft. The three kids believe that Snape wants the stone for himself in lust for power and immortality. Harry, Ron, and Hermione sadly agree that this matter will be solved in a week, with Snape succeeding to Quirrell's meekness. They try to be supportive and encouraging to Quirrell whenever possible by telling people off for laughing at his stutter, or smiling at him encouragingly whenever they pass him. Quirrell pays no mind to their sudden nice behavior. The three students come to think that Quirrell is tougher than it shows, seeing that Snape is as unhappy as ever, confirming to their perspective that the Stone is still in its place and Quirrell is keeping resistance against Snape's intimidation.

Trying to figure out how to get past Fluffy, Quirrell decides to trick Hagrid into revealing a way to tame the beast. Quirrell is in possession of a Dragon egg and disguises himself in a black robe with a large hood covering his face. At Hogsmeade, Quirrell lures Hagrid at Hog's Head Inn, and entices him to play a game of cards by wagering the dragon egg. The two have a few drinks, as Quirrell plans to get Hagrid drunk enough to talk without any suspicion. Quirrell convinces Hagrid that he is a criminal Dragon dealer, and as such, shares Hagrid's penchant for dangerous pets. Using alcohol's influence, Quirrell manipulates Hagrid by asking him if he is sure he can handle raising a dragon. A drunken Hagrid proudly tells him about how he managed to tame every creature and leaves slip that playing music would put Fluffy to sleep, inadvertently giving Quirrell the information he needs. Hagrid later assumes that 'the stranger' was in fact a Dragon dealer who needed to get rid of the illegal egg without selling it.

Throughout the year, Quirrell's body weakens drastically from hosting Voldemort's soul. With Voldemort sharing a body with him, Quirrell needs to drink unicorn's blood for his master to survive. Actually both of them need to unicorn's blood to stay alive, or Quirrell will die from his body hosting a parasite being, lower than a ghost (a damaged remain of soul). Quirrell goes to the Forbidden Forest during the nights, disguised in his hooded robe, and preys on unicorns, wounding them mercilessly with black magic and drinking their blood. Unicorns are fast and hard to chase and Quirrell, not feeling pity for the creatures, keeps them alive for convenience, to drink their blood multiple times, thus causing them to die slow and painful deaths by bleeding. The centaurs of the forest feel Voldemort's foul presence and prophesy that Harry Potter will soon die, as "it is written in the stars".

During March and April, Harry has compltely forgotten about the Philosopher's Stone's matter, especially during all the past weeks surrounding the troubles with Norbert (later Norberta) and the following days after the Dragon's departure, as he, along with Hermione and Neville Longbottom are suffering hatred and resentment from fellow Gryffindor students for making them lose 150 house points in a row. In the wait of Professor McGonagall to finally reveal what punishment they are supposed to receive, Harry gets finally reminded of the danger revolving the stone when, in May 24, he hears begging and cries coming from a castle's room: it is Professor Quirrell, breaking and agreeing to tell everything to his master Voldemort, who is punishing him over something, possibly resistance. Harry sees Quirrell rushing out the room, crying and adjusting his turban, hastily placed on his head. Not knowing the truth, Harry believes that Snape has finally succeeded into breaking Quirrell to reveal a way to get past the latter's protection of the Philosopher's Stone. Concerned, Harry immediately tells about it to Hermione and Ron, but the three of them agree that this is no longer their business and that they should denounce Snape to Dumbledore. However, they realize this would only bring out more troubles, more loss of house points, and more hatred from students, as it would confirm their investigations on forbidden matters. With no solid proof of their own against a teacher's word and believing that Quirrell would never support their accusations out of fear, the three have no choice but to remain silent.

Hagrid finds out about a unicorn killer haunting the Forbidden Forest when he finds a dead one. A week later, May 25, Harry, Hermione, Neville, and Draco Malfoy are to follow him in there as their detention. Hagrid tells them that there is something that is not supposed to be in these dark woods, as not even a werewolf is fast enough to get a unicorn. One of the unicorns attacked by Quirrell is still wandering around, and Hagrid means to find it to either save it or giving it merciful death. That same night, Quirrell is also wandering around the Forbidden Forest to the students' danger. While in the forest, Quirrell is drinking the blood of the previously wounded unicorn, who finally died of its wounds. Quirrell is disturbed by Harry and Draco, with the dog Fang to protect them. Malfoy runs off screaming with Fang following him, but Harry's scar hurts so much due to being so close to Voldemort that he can barely move and is close to faint from the pain. Knowing this is a great opportunity to act, Quirrell advances on Harry to kill him, but before he can harm him he is stopped by the centaur Firenze, who brings Harry to safety, while Quirrell flies away. After saving him, Firenze tells Harry that unicorn's blood keeps the one who drinks it alive even if they are extremely close to die, also telling Harry that the person he saw was no other than Voldemort himself. Harry realizes that Voldemort is the one behind the attempeted thefts of the Philosopher's Stone. The centaur Bane is furious at Firenze for interferring in Harry's destiny, since Voldemort is supposed to kill Harry, succeed in his plans, and return to full life, according to the stars.

About a week before Harry's exams, Voldemort orders Quirrell to try to get the Stone again. To be able to steal the stone in peace, Quirrell forges a letter for Dumbledore, stating that he is summoned by the Ministry of Magic in London, with a fake official sign. After Dumbledore leaves Hogwarts, Quirrell advances in June 4, using an enchanted harp to tame Fluffy, and then passing every following trial until the last. Quirrell passes all six chambers: Hagrid's Fluffy, Sprout's Devil's Snare, Flitwick's winged keys, McGonagall's Human Chess Game, and then Quirrell's own protection, an enormous violent mountain troll (bigger and meaner than the one from Halloween) that he easily defeats, ending with Snape's potion riddle for sharp minds with good deduction. The last is Dumbledore's chamber with the Mirror of Erised, a very tricking one, even for Quirrell.

Quirrell is unable to figure out how to take the stone from the Mirror of Erised, going so far as to consider smashing the mirror. The trick, set by the cunning Dumbledore has that the only way to obtain the stone is for an individual to look into the mirror and see themselves possessing the stone but not using it, and Quirrell sees himself using it to resurrect Voldemort. He has no doubt that this was set by Dumbledore and spends a lot of time pondering about the mirror. Meanwhile, Harry, Ron and Hermione, thinking that Snape is trying to steal the stone to use its powers and bring Voldemort back to health, had also decided that they would go after the stone themselves, after failing to have McGonagall to take action against the thief. After braving many tests, Harry, separated from Ron and Hermione, is forced to enter the last room alone. To his shock, he is not awaited by Snape or Voldemort, but by Quirrell.

Quirrell, now dropping the stuttering, weak facade, faces Harry. The boy is shocked to see Quirrell as he never knew him, completely different from the one he always met in school: no longer twitching, stuttering or timid, but evil, cruel, arrogant, power-hungry, impatient, easily angered, and hateful. Quirrell, who had always been object of derision, underration, and snobbery is visibly pleased to have a shocked attention from the first person finally witnessing how dangerous and confident he truly is. He admits to Harry that Snape is really convenient to have around with the latter's villainous-like presence that make him the perfect dark wizard. Quirrell is quick to point out that being seen as poorly skilled, particularly alongside Snape, is a very effective disguise that let him work undisturbed. Harry mentions that Snape was muttering spells while keeping eye contact during his first Quidditch match, but Quirrell reveals that he was the one who enchanted Harry's broom to kill him, that Snape only tried to save Harry with counter-curses, and that it was Hermione knocking Quirrell off his feet that interrupted the jinx. Quirrell confirms he was the one who set the troll loose into the dungeons at Halloween as a diversion, so he could see what was guarding the Philosopher's Stone, but Snape thwarted him. He brags to be very gifted with trolls, having easily defeated the strong huge one in his protection chamber. Harry is shaking in fear after hearing Quirrell's cold laugh, instead of his fake nervous one, and tries to keep talking to Quirrell in order to buy time for Hermione to reach the owlery to send a letter to Dumbledore and get the teachers to the Stone's dungeons to stop Quirrell.

Quirrell immobilizes Harry with a non-verbal spell and then again faces the single object in the chamber, the Mirror of Erised, to resume his investigation. Still confused and trying to distract Quirrell from figuring out a way to get past the mirror, Harry wonders why Snape hates him so much and Quirrell reveals to Harry that Snape and James Potter went to Hogwarts together as students and that they always hated each other and fought a lot, which is why Snape dislikes Harry, though he never wanted him dead. Quirrell points out that after Halloween, Snape was constantly keeping an eye on him, but he, Quirrell, actually is never alone. Quirrell says that "his Master", Lord Voldemort, is with him wherever he goes and knows everything about him. He explains to Harry that ever since his failed robbery at Gringotts, Voldemort punished him and remembers with fear all the times he had to face his master's wrath. Quirrell spitefully remembers his old-self, claiming he was a foolish young man until meeting Voldemort, who showed him that there is no good or evil, only power, and those too weak to seek it.

A frustrated Quirrell is unable to decode the Mirror's secret. He sees himself handing the stone to his master Voldemort, but has no idea how to acquire it. Dumbledore later reveals to Harry that only those who would want to find the stone would be able to get it, not the ones whose desire was it to use the stone, as they would only see themselves drinking Elixir or making gold. Turning back to the Mirror, Quirrell wonders how to get the Stone. At this point Voldemort, for Harry only a mysterious disembodied voice, tells Quirrell to "use the boy".

Quirrell frees Harry and commands him to stand before the mirror and tell him what he sees. Harry, who sees himself putting the Philosopher's Stone in his pocket, realizes that the stone now is in his pocket and desperately tries to deceive Quirrell by telling him that he sees that he has just won the House Cup. Voldemort however is not so easily fooled and demands that Quirrell let him speak to Harry face to face. Though Quirrell initially claims that Voldemort is not strong enough yet, he removes his turban and reveals Voldemort's face on the back of his head to Harry, who wants to scream but is too paralized with fear. Voldemort says he became like this since his first defeat and that he lived in Quirrell's body as a parasite for a year. Voldemort explains to Harry that the hooded figure he saw in the Forbidden Forest was actually Quirrell, drinking unicorn's blood on Voldemort's behalf, as Voldemort cannot do it himself. Voldemort then reveals that he knows Harry has the Philosopher's Stone in his pocket, causing Harry to try to escape. With a snap of his fingers, Quirrell conjures a wall of fire between Harry and the door, blocking the only way out.

After Harry refuses to join Voldemort (which is only Voldemort's lies anyway, as he fears Harry might become a greater dark wizard), Voldemort orders Quirrell to kill him. Quirrell seizes Harry strangles him, but to the surprise of the three, Quirrell's hands blister and burn the very moment he touches Harry. Horrified, Harry watches Quirrell screaming in agony as his skin burns and blisters, revealing flesh and blood. In pain and furious, Voldemort forces Quirrell to keep trying to kill Harry. Knowing better than getting close to Harry, Quirrell raises his hand to perform a wandless deadly curse. Desperate, Harry grabs Quirrell's face and arm, leaving the teacher in too much pain to utter the incantation. The body Quirrell and Voldemort are both sharing burns and blisters, due to the protective charm Harry's mother, Lily, left in his skin when she died for him. Quirrell, full of hatred and sharing his body with Voldemort, cannot stand Harry's touch and screams in extreme pain, while Voldemort keeps screaming to kill Harry and get the stone. The pain in Harry's scar is so intense that it renders him unconscious, while Quirrell is screaming. On her way to the owlery, Hermione had already met Dumbledore, who returned to Hogwarts on his own, and alerted him. Dumbledore, along with other unseen screaming voices heard by Harry (perhaps teachers), arrive just as Harry faints. Dumbledore wrestles Quirrell off Harry's unconcious body. He is unable to save Quirrell from death, whose body is so horribly burned that Voldemort dispossess his body and lives him to die. A bodiless Voldemort flees away from Dumbledore, while Quirrell dies of his wounds.

In the movie, Quirrell's death is made less graphic for the audience and movie's rating, his body crumbling instead of burning, thus there is no flesh and blood showing. Instead, Harry kills Quirrell by pressing both hands on the professor's face, causing him to crumble to dust. In the books, Quirrell tries to kill Harry despite the pain and is stopped by Dumbledore, who wrestles Quirrell off Harry's body, the later having become unconscious. When Voldemort leaves the mortally wounded body of his fallen servant, Quirrell dies. Also, instead of a wall of fire, Quirrell conjures mystic ropes that binds Harry.

After Harry reawakens in the Hospital Wing of Hogwarts, Dumbledore explains to him that Quirrell was unable to touch him because when Harry's mother died for him, she created a powerful protection by her sacrifice. As Harry was protected by pure love, Quirrell, who was ambitious, evil and cruel was unable to touch him without suffering great pain. However, despite being effectively turned into a living Horcrux for the last year of his life, Quirrell did not ultimately lose his soul, having even tried to put up feeble resistance on occasion (in spite of the fact that Voldemort was far too strong for him). At the end, Quirrell still died with his soul intact.

Post Mortem
Quirrell's position as Defense Against the Dark Arts' teacher is taken by Gilderoy Lockhart the following year, in Harry Potter and the Chamber of Secrets.

Although he saw Quirrell as little more than a disposable lackey, Voldemort acknoweldges Quirrell's service in Harry Potter and the Goblet of Fire. At Little Hangleton's graveyard, the resurrected Voldemort summons many wizards and witches who used to be Death Eaters before his first defeat. Voldemort lets them know his anger on their false loyalties and exclusive self-interests, especially Lucius Malfoy. While Voldemort explains the Death Eaters what happened to him during the last 13 years, while he was disembodied, he describes his stay on the back of Quirrell's head and explains that Quirrell died when he left his body. Quirrell was one of those servants who remained loyal, however Quirrell had his own desire and ambition for greatness, unlike more fanatical servants like Bellatrix Lestrange, Barty Crouch Jr., Rodolphus Lestrange, Rabastan Lestrange, and Antonin Dolohov, who put Voldemort's interest before everything else, even at their own damage.

In Harry Potter and the Order of the Phoenix, Harry, Ron, and Hermione discuss who will be the new Defence Against the Dark Arts teacher. Fred and George run down the list on teachers known by Harry and his friends: Quirrell who died, Lockhart that lost his memory, Lupin who resigned because he was going to be fired anyway, and Alastor Moody who was kept imprisoned and cursed for nine months. The twins make no mention of their two previous teachers before Quirrell.

In the same novel, in late 1995, the then Defence Against the Dark Arts professor, Dolores Umbridge mentions Quirrell when she criticizes the past DADA professors for not teaching them things that would pass a Ministry inspection. Umbridge however, considers that Quirrell was a possible exception due to teaching "age-appropriate subjects". But this was also when Quirrell pretended to be an extremely mediocre wizard when he had Voldemort's knowledge. Harry retorted to Umbridge in class that Voldemort was on the back of Quirrell's head, earning him another week's detention.

Always in Order of the Phoenix, Quirrell is often mentioned when Harry and his friends speculate about Voldemort possessing bodies. Remembering Quirrell's turban, Harry wonders how the professor felt and lived with Voldemort being constantly inside him and his mind, sharing everything and thoughts together. Imagining this, Harry feels dirty and contaminated. Thinking only about Quirrell and his own dreams about Voldemort, Harry completely forgets that Ginny Weasley was also possessed by Voldemort's piece of soul in her first year at Hogwarts and Ginny reminds him later about it during Christmas.

In Harry Potter and the Half-Blood Prince, Bellatrix confronts Snape on his role during Voldemort's plot to steal the Philosopher's Stone. She knows that Snape interferred with Quirrell's work multiple times and thus she (correctly) believes Snape to be traitorous and that Voldemort is wrong in trusting him. Snape lies to Bellatrix and Narcissa, explaining that he was simply playing his role and that he and Quirrell were just rivals for Voldemort's favor. Snape states that Voldemort had chosen the "mediocre" and "inept" Quirrell over him and that it did no good to either Voldemort and Quirrell at the end.

In the same novel, Horace Slughorn does not want to return to Hogwarts due to the harsh treatment of teachers from the previous years. To convince Slughorn that Hogwarts is safe from Death Eaters, Harry tells him that Professor Quirrell is the only teacher who has died at Hogwarts and that the reason he died was because he was following Voldemort's orders. Quirrell being the only teacher who died in the school is not strictly true, as Professor Binns clearly died at the school, though as it was of natural causes it would not concern Slughorn either way. Quirrell's death as a Hogwarts' teacher is the only one Harry knows of that could be attributed to Voldemort and his organization.

Appearance
Quirrell was a young man with light blue eyes and very pale skin. When Quirrell returned from his sabbatical in Albania, one of his eyes developed a twitch and his skin became quite pale. At the start of the term, he wore a purple turban. Near the end of his life, it was revealed under his turban that he had allowed Voldemort's fledging body to grow a face at the back of his own head and joined forces with him.

Trivia

 * J.K. Rowling stated that Quirrell was partly an Horcrux, because he was holding a piece of Voldemort's soul inside him. So, it can be said that Quirrell was the first Horcrux that Harry destroyed instead of Tom Riddle's Diary. However, considering the story's logic, Quirrell cannot be one, since Horcruxes hold the parts of a wizard's soul that aren't with its conscience, and the one with Quirrell was the soul part which was Voldemort himself, soul and conscience. So when Harry touched Voldemort's bodily Horcrux, Quirrell ceased to exist.
 * In the movie, Quirrell has no part in the protection of the Philosopher's Stone. The part with the knocked out troll is missing.
 * In the books Harry is able to shake Quirrell's hand at the Leaky Cauldron as Quirrell was not sharing his body with Voldemort yet. However, in the movie Quirrell already wears his turban and therefore refuses to shake Harry's hand.
 * Archive footage of Quirrell sitting next to Snape in Harry Potter and the Philosopher's Stone is used in Harry Potter and the Deathly Hallows: Part 2. This footage continues with Quirrell turning into black smoke and disappearing to create the effects that this scene is a memory of Snape.
 * The name "Quirinus" is possibly derived from the Sabine word quiris meaning "spear". Quirinus was a Sabine and Roman god who was later identified with Mars. The name was also borne by several early saints.
 * Professor Quirrell was the second-to-final boss in the Gameboy color adaptation of Harry Potter and the Philosopher's Stone. Voldemort uses Quirrell's body to fight Harry as the final boss.
 * He is also the only boss who can use level 3 magic (tria magic).
 * In this version, Harry meets Quirrell at Diagon Alley twice, while the latter is wearing his hooded dark robe to disguise himself. He owns Vault 998 in the new vault area of Gringotts Wizarding Bank. He possessed various belongings, including Circe's Chocolate Frog Card that was given by Professor Cuthbert Binns (History of Magic's teacher) to James Potter before Quirrell came into possession of it. Besides Gringotts' defenses, Quirrell secretely keeps his own monsters in his vault.
 * In the PS1 video game of Harry Potter and the Philosopher's Stone, Quirrell makes several appearances in his hooded robe and a mask. He tries to kill Harry different times, by transfigurating stone gargoyles and armors or sending Harry to trolls in the school's dungeons. He is also presumably the dark wizard who blocks Harry in the dungeons, by putting a curse, though it is never confirmed ingame.
 * In the PS2 video game of Harry Potter and the Philosopher's Stone, Quirrell summons Gytrashes, who are large, vicious, nocturnal and possibly ghosts, white dogs, to kill Harry. The Gytrashes follow Quirrell's commands.
 * Harry was in his cot when his mother died, but he would not remember this due to his age at the time. So Harry has no memory of deaths until he sees Professor Quirrell die in the movie adaptation of Harry Potter and the Philosopher's Stone, unlike the novelization in which Harry passes out before he sees Quirrell dying. However Harry is unable to see the Thestrals until the movie adaptation of Harry Potter and the Order of the Phoenix, after witnessing Cedric Diggory's death. This was likely a mistake from the movie directors of the first film, and possibly even from J.K. Rowling not informing them, as the fifth book was not released at the time. However, it is also possible that after passing out, Harry could no longer remember seeing Quirrell dying, though it seems highly unlikely, as Harry never asks Dumbledore what happened in the dungeons, like his book counterpart does and seems to know that Quirrell passed out.
 * Furthemore, while Cedric's death is the first death Harry witnesses in the book series, Harry is still unable to see the Thestrals until Harry Potter and the Order of the Phoenix, because the reality of Cedric's death has not fully sunk in. Technically, however, Harry did not witness the event at all in the books, as he was described to have his eyes closed with agony during Cedric's actual death.
 * In Jimmy Neutron Carl played a character based on Quirrell and Tom Riddle from the Chamber of Secrets (with the former being a vessel for Voldemort and the later being an Incarnation of Voldemort).
 * WatchMojo.com listed Quirinus Quirrell as #9 on their Top 10 "Most Evil Harry Potter Characters" list.