Lord Voldemort AKA Tom Riddle is the most powerful and feared dark wizard in history. So great is the terror Voldemort inspires, the vast majority of witches and wizards refuse to call him by his name, often referring to him as You-Know-Who or He-Who-Must-Not-Be-Named. Voldemort possesses prodigious magical skill, and is near impossible to kill, or even injure, though his greatest weaknesses are his fear of death and inability to understand love.
Born from a loveless marriage, Tom Marvolo Riddle is orphaned immediately after his birth, and raised in a Muggle orphanage, which he detests. Learning of his magical ability, but not initially understanding it, from a young age, he uses his power to terrify and bully the other children as well as steal from them. This continues until he is around eleven, when Albus Dumbledore arrives to offer Tom a place at Hogwarts School of Witchcraft and Wizardry. Tom eagerly accepts and arrives at Hogwarts in the following months. With his magical skill and ability to charm people, Riddle becomes popular with many of the teachers, bar Dumbledore, who keeps a careful eye on him. Tom becomes obsessed with learning of his parentage, and after accepting that his father (who he is named after) is not a wizard, he fashions himself a new identity through rearranging the letters of his name: Tom Marvolo Riddle is twisted into I Am Lord Voldemort, and Riddle begins using the name among his most intimate companions at Hogwarts. After learning of the creation of Horcruxes from the unwilling Professor Horace Slughorn, Riddle travels to Little Hangleton in search of his wizarding grandfather, Marvolo Gaunt. He learns about his father from his uncle, Morfin, and after cursing Morfin and stealing Marvolo's ring from him, he travels to Tom Riddle Senior's house and kills his father and grandparents, creating his first Horcrux from the ring in the process. Upon his return to Hogwarts, now with the knowledge that he is descended from Salazar Slytherin, he opens the Chamber of Secrets and unleashes the Basilisk within, killing a girl named Myrtle and creating a second Horcrux from his diary.
Following his graduation from Hogwarts, and failed attempt to stay on as a teacher, Riddle takes a position working at Borgin and Burkes, where his skill at charming people comes in handy when persuading them to part with their treasures. He sets his sights upon the old and rich Hepzibah Smith and surreptitiously acquires from her a golden cup once belonging to Helga Hufflepuff, and a locket belonging to Salazar Slytherin,which he views as his by right. Follwing Hepzibah's death, and the creation of more Horcruxes, Riddle disappears for several years and begins forming his Death Eater army, eventually re-emerging near unrecognisable and completely immersed in his Voldemort persona. After being refused the position of Defence Against the Dark Arts teacher at Hogwarts by Dumbledore, Voldemort places a jinx upon the job out of spite and begins a massive attempt to take over and recreate the wizarding world in his own image. He is thwarted almost every step of the way by the Order of the Phoenix, but his downfall comes in the form of one year old Harry Potter. Upon learning of a prophecy that a boy born at the end of July will able to kill him, Voldemort sets his sights upon Harry and makes plans to kill the Potters. James and Lily fall, but Lily's love for her son and willingness to die for him forms an invisible protection for Harry and Voldemort's curse fails, rebounding upon its caster. Ripped from his body and reduced to mere shadow and vapour, Voldemort flees, unaware that he has inadvertedly turned little Harry into another Horcrux.
Voldemort reappears almost eleven years later, now sharing a body with Professor Quirinus Quirrell in the hopes of stealing the Philosopher's Stone and returning to full strength. He is strengthened by Quirrell drinking unicorn blood in the Forbidden Forest, but is thwarted again by Harry, who Quirrell, sharing a body with Voldemort, cannot touch. Voldemort leaves Quirrell for dead and retreats again, going into hiding in the forests of Albania, where he attempts to take shape by possessing small animals, snakes being a favourite. However, the possessions do not last long and his hosts die in the process. Salvation comes for Voldemort two years later in the form of Peter Pettigrew, AKA Wormtail, an old servant of Voldemort's who betrayed the Potters and whom much of the wizarding world believes dead. Under Voldemort's guidance, Wormtail creates a potion that returns the ruined Dark Lord to a weak physical form and soon he is brought back to England. They hide in Little Hangleton in the remains of the Riddles' old house for the best part of a year, formulating a plan for Voldemort's resurrection, and he creates his final Horcrux there in the form of his snake Nagini, following the murder of Frank Bryce, the muggle caretaker. The following summer, in the final stage of the Triwizard Tournament, Harry Potter is warped by Portkey, along with his fellow Triwizard champion, Cedric Diggory, to the graveyard of Little Hangleton. Cedric is immediately killed, and Harry is involved in a ritual that returns Voldemort to full strength, his blood being the final stage of the process. Now able to touch Harry freely, the resurrected Voldemort tortures him for a while before forcing him into a duel. However, because both Harry and Voldemort's wands share feathers from the same phoenix, their spells clash, and Harry is able to escape with Cedric's body thanks to the intervention of the shades of Voldemort's last victims and return to Hogwarts to alert Dumbledore.
Voldemort remains quiet for a year, dwelling endlessly on the prophecy which foretold the coming of the one who could kill him, and his visions of the Department of Mysteries plague Harry almost every night. Coming to understand this link, Voldemort plants a vision in Harry's mind of his godfather, Sirius Black, being tortured, at which point Harry immediately goes to his rescue. After a series of battles with the Death Eaters, Harry comes face to face with Voldemort again who takes part in a spectacular duel with Dumbledore. Seeing that they are evenly matched, Voldemort tries possessing Harry in the hope that Dumbledore will kill the boy, but Harry's desire to see the recently deceased Sirius again drives Voldemort out, and he flees. Over the next year, Voldemort begins more aggressive attacks upon both the wizarding and muggle worlds, and gives Draco Malfoy a special mission: To murder Dumbledore. When Draco is unable to, Severus Snape steps in and finishes the job. Voldemort then sets about taking over the Ministry of Magic while trying to find the legendary Elder Wand in order to kill Harry. He eventually succeeds in the latter, breaking into Dumbledore's tomb and stealing the wand. However, he is unaware that Harry knows about the Horcruxes and is trying to destroy them on Dumbledore's orders. He is only made aware after Harry, Ron and Hermione very publicly break in and out of Gringotts after stealing Hufflepuff's cup.
After checking on the safety of his other Horcruxes, which have almost all been stolen or destroyed, Voldemort launches a full-scale offensive upon Hogwarts. The battle rages on long into the night after the denizens of Hogwarts won't surrender Harry to him, and he eventually calls an hour long cease-fire after killing Snape, ordering that Harry present himself immediately in the Forbidden Forest. When Harry does so, Voldemort casts the killing curse upon Harry, unknowingly destroying the fragment of soul within him. Unaware that Harry is still alive, he returns to the castle, bringing Harry, who is playing dead, and the battle begins anew as the Order and students of Hogwarts are still unwilling to surrender. Following the death of Nagini thanks to Neville Longbottom, Voldemort clashes with Harry one final time. However, as the Elder Wand doesn't recognise Voldemort as its master and sees Harry as such, it will not kill Harry and directs the killing curse back at Voldemort. Finally dead, Voldemort literally disintegrates and his remains are scattered upon the wind.
- In the original novel of Harry Potter and the Deathly Hallows, Voldemort does not disintegrate upon his death. He merely falls to the floor dead 'with a shrunken finality.
- JK Rowling has stated that Voldemort's spirit is doomed to linger forever in a limbo Harry visited after being struck by the killing curse in the forest. In this state Voldemort resembles a small naked child with raw, bloodied and flayed looking skin.