He attached himself after Quirrell failed to steal the Stone from Gringott's. Hagrid had removed it from the vault earlier that day. Voldemort was able to attach himself to Quirrell when he failed to wash his hands after using a public lavatory.
Quirrell ticked a few boxes which ultimately led Voldemort choosing him as his physical vessel: He was the only one who came searching for him. He underestimated Voldemort's power. Quirrell's standing as a Professor in Hogwarts helped him to gain access to one of the most secure places.
Quirrell never lost his soul to Lord Voldemort, but he lost his body and ended up completely subjugated by Voldemort, with his head mutilated and Voldemort able to see out of the back of his head, forcing him to wear a turban.
Overall, Voldemort was desperate to get his hands on the Stone to restore his body, his power and to try to find a way to beat death.
Voldemort wasn't aware of Harry being a pseudo-horcrux because he didn't plan it, and Harry didn't know either until Voldemort “killed” him, but he actually killed the piece of soul kept in him.
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.
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 Barty Crouch Jr. and Peter Pettigrew.
Snape did not know Quirrell was hosting Lord Voldemort during the events of Book 1.
Voldemort's past, as revealed by the books, is shrouded in mystery and guesswork. In fact, at the beginning of the series, barely anyone but Dumbledore and Hagrid knew that Voldemort was the charming, successful Tom Marvolo Riddle.
The scar is also a symbol of Harry's emotional sensitivity, because it hurts him whenever hatred is directed at him, as when Snape first sees him at Hogwarts or when Quirrell tries to grab him.
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.
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.
Dumbledore knew that Quirrell was possessed by Voldemort and purposely set things up for him to reach the Philosopher's Stone.
We also know and can conclude that based on the following excerpt that Voldemort was once again, reverted into a disembodied soul, unable to use magic as he did not have any physical form.
The Dark Lord — aka Voldemort — created seven Horcruxes in an attempt to sustain immortality.
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.
Snape's fierce devotion to and love of his childhood friend Lily, Harry's mother, is the foundation of that loyalty. After Harry Potter and the Half-Blood Prince, Snape's loyalty was a matter of intense debate among the fans.
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.
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.
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.
Draco Malfoy
Draco becomes a Death Eater in his sixth year at Hogwarts and is assigned to kill Dumbledore.
Draco Malfoy's mother Narcissa was cold, cunning and devoted to the Dark Lord. But she was also a mother, which meant she was willing to risk everything to make sure her son was safe. When Harry survived Voldemort's Killing Curse for the second time, Narcissa pretended he was dead so she could get to Draco.
Who is immune to Avada Kedavra? 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.