Lord Voldemort, obsessed with immortality and inability to understand the importance of the soul's well-being, went further than any wizard known to history to create seven — although he had an eight-part soul, because he accidentally created his sixth Horcrux when he failed to kill Harry Potter in 1981,^[4] and later made his pet snake Nagini into what he thought was the sixth, but was in fact the seventh, Horcrux. As a student named Tom Marvolo Riddle at Hogwarts in the 1940s, he learned of Horcruxes through books in the Restricted Section, including Secrets of the Darkest Art, and sought out Potions master Horace Slughorn for further information about creating more than one, of which no book would have any record. Albus Dumbledore removed those books from the Hogwarts Library soon afterwards. Although later he suspected that Slughorn had given information to Riddle about Horcruxes, Slughorn refused to reveal the true account of what really happened. Dumbledore later assigned Harry to retrieve the stored memory of it during the 1996–1997 school year. Harry was able to get it through the use of Felix Felicis.

This was part of Dumbledore and Harry's quest to determine, locate, and destroy, in secret, what they believed to be as many as six of Voldemort's Horcruxes. After Dumbledore's death, Harry took up the quest with his friends Ron and Hermione. Hermione was able to Summon the books on the subject to her from the Headmaster's office at the end of the 1996–1997 school year to aid them in their research on Horcruxes.^[4]

Although Voldemort had seven Horcruxes, no more than six existed at one time because Tom Riddle's diary was destroyed before Nagini was turned into a Horcrux. Hence he did have his soul split in seven pieces as he intended; however, it conferred no special added protection as he seemed to feel it might.^[5] Concerning Nagini, it is not known if she had to have been killed by Godric Gryffindor's Sword or if any other means, such as a regular sword killing her, would have destroyed the Horcrux. However, as Albus Dumbledore stated, using a living being as a Horcrux is a risky business, due to it being able to move around and think for itself. It is unknown if any method that would normally kill Nagini would also destroy the Horcrux.

All of Voldemort's Horcruxes are made from objects that have extreme value, in his desire to secure his position as the greatest in history, and that only noteworthy items can live up to his standards and having the honor of housing a fragment of his precious soul. As such, he had originally made it his desire to collect four items of the four founders of Hogwarts; he found only three, and gave up after failing to find another, but made Horcruxes out of other items that have sentimental value to himself, if not as a priceless artifact of the Wizarding world. Believing the number seven is the most powerful, Voldemort intended to split his soul into seven pieces, with six Horcruxes housing one fragment each and his main body the seventh. He hid these Horcruxes in special locations and kept their existence and purposes from absolutely everyone. However, his arrogance has also inadvertently let him leave behind subtle hints of their whereabouts, leading to their demises.