ems Harry burnt Quirrell's face when he touched it. That worked because when Lily was killed, she had tried to protect Harry and therefore gave him the most powerful weapon against Voldemort; Love.
At the time Harry touched him, Quirrell was sharing a body with Voldemort. Since the magical blood protection Harry had prevented Voldemort from touching him, Quirrell would suffer pain. He would ultimately be destroyed from touching Harry.
He explains also that Quirrell could not touch Harry because Harry was protected by his mother's love.
In the books it says that Quirrell shakes Harry's hand, and this doesn't effect him because he isn't yet possessed by Voldemort.
Voldemort was able to attach himself to Quirrell when he failed to wash his hands after using a public lavatory.
Quirrell didn't use the Killing Curse on Harry, because Voldemort said “use the boy” to get the Sorcerer's stone from the Mirror of Erised. If Quirrell had killed Harry right away, he would have lost the chance to get the stone.
It should be noted that despite his fear of Voldemort and that he was not a Death Eater, Quirrell was one of Voldemort's only followers who referred to him by name, the others being Bartemius Crouch Junior and Peter Pettigrew.
He wanted Quirrell to proceed with what he was doing in an attempt to gather intelligence in case there was a bigger force at work behind it. Dumbledore had full confidence in his abilities and probably thought he would be able to stop Quirrell at any point if he truly needed to.
Voldemort's desire to beat death and become immortal was also why he and Quirrell ended up slaying innocent unicorns. Drinking the blood of a unicorn would keep someone alive – even if they were an inch from death.
Snape did not know Quirrell was hosting Lord Voldemort during the events of Book 1. He tried to stop Quirrell from acquiring the Sorcerer's Stone on Dumbledore's orders.
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.
He is an exceptionally skilled wizard whose extremely cold and resentful exterior conceals deep emotions and anguish. A Professor at Hogwarts School of Witchcraft and Wizardry, Snape is hostile to Harry due to his resemblance to his father James Potter, who bullied Snape during their time together at Hogwarts.
Her sacrifice gave Harry the power of love, a protection spell sealed with the blood spilled by her death.
Hagrid later becomes friends with Ron and Hermione as well. Later in the book, a hooded person (Quirinus Quirrell in disguise) gives him a dragon egg to elicit details about Fluffy.
History. Quirinus Quirrell's classroom, as well as his turban, were said to smell strongly of garlic, which many students believed was to protect against a vampire Quirrell claimed to have met on his travels in Romania.
This theory suggests that each time he created a new Horcrux, that specific Horcrux diminished a part of his soul. Thus, his nose began to sink in, eventually disappearing altogether. Due to his tampering with dark magic, his human appearance evolved into a more snake-like state.
When they reach Fluffy, Harry, Hermione, and Ron notice a harp by his feet and realize that someone has already passed by Fluffy. Harry plays a flute he has brought, putting Fluffy to sleep and allowing his gang to go through the trapdoor.
After he regains his body in the fourth book, Rowling describes Voldemort as having pale skin, a chalk-white, skull-like face, snake-like slits for nostrils, red eyes and cat-like slits for pupils, a skeletally thin body and long, thin hands with unnaturally long fingers.
He was once again a disembodied soul, unable to use magic as he did not have any physical form, weak and helpless. He only managed to regain a weak human form as seen in the Riddle house when Wormtail helped him concoct a potion.
He didn't need to tell Dumbledore his suspicions because Dumbledore was already well aware: it was Dumbledore who asked him to keep an eye on Quirrell. It's explained in the last book.
He has grown afraid of Harry's connection to Voldemort. Perhaps Voldemort, knowing Dumbledore's love for Harry, would possess Harry and provoke Dumbledore to kill him. So, Dumbledore attempted to avoid Harry throughout Book 5 for Harry's own good.
The reason why Quirrel could safely shake Harry's hand at the beginning of the book is because Voldemort didn't actually start possessing Quirrel until after Quirrel failed to steal the Philosopher's Stone from Gringotts. Very simple.
The villain in the "Fantastic Beasts" movies is Gellert Grindelwald, who played a small but crucial role in the "Harry Potter" series. He was the wizarding world's biggest villain before Voldemort came along. In his youth, Grindelwald was friends with Albus Dumbledore, who was in love with him.
Quirrell is, in effect, turned into a temporary Horcrux by Voldemort. He is greatly depleted by the physical strain of fighting the far stronger, evil soul inside him.
As he was a relatively weak-willed wizard, Quirrell attempted to attain distinction by attaching himself to a powerful being, though that power instead latched itself onto him. Quirrell was never seen performing magic, so it is uncertain how powerful a wizard he actually was.