There were 8 horcruxes. 7 were made by Voldemort intentionally ( Nagini, goblet, diary, locket, ring, diadem and the part of his soul in Voldemort himself) and 1 was made accidentally which was Harry.
The Dark Lord — aka Voldemort — created seven Horcruxes in an attempt to sustain immortality.
Voldemort only ever intended to make six Horcrux, with the possibility that maybe he could create more in the future. However, when Voldemort attempted to kill baby Harry that fateful night, his killing curse backfired instead.
Believing that the number seven is the most powerful number when it comes to magic, Voldemort intended to split his soul into seven pieces, with six Horcruxes housing one fragment each and his body containing the seventh.
Harry was the unintended 8th horcrux, due to his souls being so unstable by being split more than once. The other 6 horcruxes are: HuffleCup.
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.
A Horcrux is considered destroyed when it's damaged beyond repair. In the case of living Horcruxes, “damaged beyond repair” would mean dead. So, yes, Avada Kedavra can destroy a Horcrux, as long as that Horcrux is a living being.
We learn from The Dark Lord that Avada Kedavra, literally, severs the SOUL from the body. THAT is why it causes instant death.
In an interview, J.K. Rowling revealed that it was the murder of Bertha Jorkins that made Nagini a Horcrux. After Voldemort discovered his Horcruxes were in danger, Nagini was magically protected, described as being encased in a 'starry, translucent sphere'.
In 1998, Fred participated in the Battle of Hogwarts, defending the castle's passageways with his twin. While fighting alongside his brother, Percy, he was killed in an explosion possibly caused by Death Eater Augustus Rookwood.
Horcrux: Quirinus Quirrell
This Hogwarts professor literally became a Horcrux when Voldemort decided to share his body. Quirrell was unable to resist Voldemort's will and was forced to do his evil deeds.
It's later revealed that Nagini was never an ordinary magical snake from start, as she was once in fact, a human (possibly a Witch) who became a snake as she is now as result of a blood curse and trapped in that form for the rest of her life.
This is extracted from the wiki. So, when Voldemort died when tried to kill Harry, he commited murder, well. But noone was there to make the spell that take your splitted soul into a container. So Harry is just a weirs soul container, but not a Horcrux itself.
Rowling said in an interview that Dumbledore was about 150 years old. However, on her website, she states that Dumbledore was born in 1881, making him either 115 or 116 at the time of his death.
After murdering a schoolgirl called Myrtle, with the help of the ancient monster that dwelled within the castle, the Basilisk, his soul was split for the first time. The object that enveloped a piece of his soul was a simple diary, one that he attained from a Muggle bookshop.
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.
In order to conjure the avada kedavra curse, you have to want to kill your victim. We all know that Voldemort could easily kill a child without an ounce of remorse... but not Snape. Snape didn't want to kill Dumbledore, and this was why the spell was blue instead of the usual green.
I've always suspected Molly's lethal spell was a particularly well-placed and powerful stunner that stops Bellatrix's heart, which is consistent with the description of her death: Molly's curse soared beneath Bellatrix's outstretched arm and hit her squarely in the chest, directly over her heart.
Though Harry encountered many opportunities that deemed Avada Kedavra necessary, it remains as one of the Unforgivable Curses Harry Potter never cast. For one, he viewed the spell as an immoral practice commonly used by users of the Dark Arts.
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.
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.
He explains also that Quirrell could not touch Harry because Harry was protected by his mother's love.
She was sorted into Slytherin House at Hogwarts School of Witchcraft and Wizardry and hated her time at the school due to never being given any positions of power. After her time at Hogwarts, Umbridge rose to prominent and influential positions in the Ministry of Magic in the Improper Use of Magic Office.