He was born as Tom Marvolo Riddle, the last descendant of the wizard named Salazar Slytherin, one of the founders of Hogwarts School of Witchcraft and Wizardry. Voldemort appeared either in person or in flashbacks in each book in the series, except the third, Harry Potter and the Prisoner of Azkaban. Voldemort has also appeared in all the corresponding film adaptations as of present date, except the third.

In the series, Voldemort is the main enemy of Harry Potter, who according to a prophecy has the power to defeat him. The wizarding community fears him so much that they refuse to refer to him by his name, instead saying "You-Know-Who" or "He-Who-Must-Not-Be-Named." Even his followers only refer to him as "The Dark Lord".

Personality

Voldemort is ruthless, sadistic, and bloodthirsty; he is willing to kill even his own henchmen, who serve him out of a mixture of fear and respect. Rowling described him as "the most evil wizard for hundreds and hundreds of years"She elaborated that he is a "raging psychopath, devoid of the normal human responses to other people's suffering" who is able to attract cowardly but cruel minions, like "Wormtail, who out of cowardice will stand in the shadow of the strongest person." What seems to drive him is his megalomaniacal sense of entitlement. He believes he is superior, and frequently refers to himself in the third-person as "Lord Voldemort." Rowling alluded to this saying that Voldemort is "incredibly power hungry. Racist, really", and holds human life in utter disregard.Rowling has also stated that if Voldemort looked into the Mirror of Erised (the mirror that reflects a person's greatest wish), he would see "Himself, all-powerful and eternal. That's what he wants."

J.K. Rowling, also stated that the fact that Voldemort was conceived under a love potion is related to his inability to understand love; it is "a symbolic way of showing that he came from a loveless union – but of course, everything would have changed if Merope had survived and raised him herself and loved him. The enchantment under which Tom Riddle fathered Voldemort is important because it shows coercion, and there can’t be many more prejudicial ways to enter the world than as the result of such a union".

Rowling said that Voldemort's boggart would be his own corpse. She also said: "Voldemort's fear is death, ignominious death. I mean, he regards death itself as ignominious. He thinks that it's a shameful human weakness, as you know. His worst fear is death". According to Rowling, the difference between Harry and Voldemort is that Harry accepts mortality, and thus Harry is in the end stronger than his nemesis: "[T]he real master of Death [i.e. someone like Harry] accepts that he must die, and that there are much worse things in the world of the living.

Magical abilities and skills

Throughout the series, Rowling establishes Voldemort as a supremely powerful, intelligent, and ruthless Dark Wizard. He is also known as one of the greatest Legilimens in the world and a highly accomplished Occlumens, and is thus able to read minds as well as shield his own from penetration. However, in the seventh book, he loses control, allowing Harry to see occasionally through his eyes and hear his thoughts.Voldemort can fly without support, defying the law of magic that states only objects can fly through use of a flying charm. Voldemort first exhibits the ability to fly while in pursuit of Harry Potter over Little Whinging. He has the ability to speak over a vast area, sounding (to the recipient) as though he were standing next to them. He does this in Harry Potter and the Deathly Hallows when he speaks to Hogwarts and the surrounding area of Hogsmeade.In addition, Voldemort is a Parselmouth, a trait he inherited from his ancestor, Salazar Slytherin. It seems that most of his Gaunt ancestors inherited this highly unusual trait: such traits are commonly passed down through families through inbreeding, a practice employed by the Gaunt Family. When Voldemort attempts to kill Harry, turning him into a Horcrux, his ability to speak Parseltongue is passed to Harry through the small bit of the former's soul. After that bit of soul was destroyed, Harry loses this ability. Voldemort shows himself capable of holding his own well even against an Elder Wand-wielding Albus Dumbledore. Voldemort claims he has experimented and pushed the boundaries of magic farther than they had ever been pushed. Albus Dumbledore states that Voldemort's knowledge of magic is more extensive than any wizard alive, and that even Dumbledore's most powerful protective spells and charms would not likely be sufficient if Voldemort returned to full power.

On her homepage, Rowling wrote that Voldemort's wand is made of yew, whose sap is poisonous and which symbolises death. It forms a deliberate contrast to the wand of his nemesis Harry Potter, whose wand is made of holly, which she chose because holly is alleged to repel evil.

Rowling establishes in the books that Voldemort is magically connected to Harry Potter via Harry's forehead scar. He disembodies himself when his Killing Curse targeting Harry Potter rebounds on him, leaving the scar on Harry's forehead. In the books, Harry's scar serves as an indicator of Voldemort's presence: it burns when the Dark Lord is near or whenever Voldemort is feeling particularly murderous or exultant. According to Rowling, by attacking Harry when he was a baby Voldemort gave him "tools [that] no other wizard possessed – the scar and the ability it conferred, a magical window into Voldemort's mind." Rowling also has established that Lord Voldemort and Harry Potter are distantly related through their ancestors, as most wizards are.

appearance

After he has regained his body in the fourth book, Rowling describes Voldemort as having very 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. As mentioned in the first chapter of the seventh book, he also has no lips. Earlier in life, as seen through flashbacks contained in the second and sixth books, Tom Marvolo Riddle is described as very handsome which is seemingly an inherited trait from his father, for his mother "...was no beauty". The transformation into his monstrous state is believed to have been the result of creating his horcruxes, becoming less human as he continued to divide his soul.

The Riddle family

The Riddle family consisted of old Mr and Mrs Riddle (named Thomas and Mary Riddle in the film adaptation of the fourth novel) and their son, Tom Riddle (Senior). They owned over half of the valley in which the town of Little Hangleton lay, and Thomas was the most prominent inhabitant of that town. They lived in The Riddle House, a large house with fine gardens, and were very unpopular locally, due to their snobbish attitudes. Tom, apparently the only child of Thomas and Mary, certainly indulged in the typical pursuits of the upper class in the first half of the twentieth century, socialising with attractive women of his class, riding horses, and enjoying his status in the town.

Rowling revealed in Harry Potter and the Half-Blood Prince that young Merope Gaunt made efforts to get as close to Tom as she could, peering at him through the windows and bushes at every opportunity. Morfin noticed his sister's affection for Tom Riddle, and hexed Tom as he rode by, covering him in hives. As surmised by Dumbledore, once Merope was alone she was able to make her move for Tom Riddle. She offered Tom a drink laced with a love potion as he rode by one day without his attractive companion, Cecilia. He became infatuated with Merope and they eloped. Within three months of the marriage, Merope became pregnant. Merope decided to stop giving Tom the love potion; she either believed that he had fallen in love with her on his own or he would at least stay for their unborn child. She was wrong, and Tom quickly abandoned his pregnant wife and went home to his parents, claiming to have been "hoodwinked" and tricked into marrying Merope.

Readers first know about the doom of the Riddles in the beginning of Harry Potter and the Goblet of Fire. Tom Riddle Sr and his parents were murdered by Tom Marvolo Riddle himself; however it was the Riddles' gardener Frank Bryce who was blamed for the murders in the Muggle world,while in the Wizarding world Morfin Gaunt was framed for this.

The Gaunt family

Most of the House of Gaunt background is exposed in Harry Potter and the Half-Blood Prince through Dumbledore's Pensieve. The Gaunts were once a very powerful and influential family, the last known descendants of Salazar Slytherin, but were reduced to poverty, as shown in the Pensieve's memory that Harry Potter and Dumbledore witnessed.

Marvolo Gaunt was the last Gaunt family patriarch. Marvolo was sentenced to prison in Azkaban for his role in an assault upon Ministry of Magic officials. He died soon after returning home. His signet ring passed to Morfin Gaunt, who was convicted on the grounds of assaulting a Muggle, and later died in Azkaban after being convicted again, this time for the murder of Tom Riddle Sr and Riddle's parents, a crime actually committed by his nephew. The truth was discovered much later by Dumbledore, who visited Morfin at Azkaban to gather information about Voldemort. After Dumbledore successfully extracted Morfin's memory of his encounter with his nephew, he tried to use the evidence to have Morfin released, but Morfin died before the decision could be made. As he was the last male Gaunt, the House of Gaunt ended with Morfin's death.

Merope Riddle was the daughter of Marvolo, sister of Morfin. Harry's first impression of her was that she looked "like the most defeated person he had ever seen", probably due to the fact that she lived in raggedness, squalor and abuse. She married Tom Riddle Sr. and became pregnant within three months of the wedding.The narrative suggests that she had tricked her husband by using a love potion, but when she became pregnant, she decided to stop administering the potion. The author also implied that Merope had grown tired of living a lie and thought that he might have stayed for the sake of their unborn child; however he left her. Desperate after her husband had abandoned her, Merope wandered through the streets of London. All she had with left was the heavy gold locket that had once belonged to Salazar Slytherin, one of her family's most treasured items, which she sold for a very small amount of Magical money. By the time she was due to give birth, she stumbled into a Muggle orphanage; within the hour, she gave birth to her only son, Tom Marvolo Riddle, and died within the next hour.

The Gaunts and Lord Voldemort are distantly related to Harry Potter because all of them are descendants of the Peverell brothers.