Lord Voldemort

Birth name: Tom Marvolo Riddle. While in school, Riddle rearranged the letters in this given name into "I am Lord Voldemort [...] a name I knew wizards everywhere would one day fear to speak, when I had become the greatest sorcerer in the world!" (PS17)

Birthdate: Dec. 31 (HBP13), c. 1926 (formula: events of 1943 referred to as "fifty years ago" in 1992). [more information on Voldemort's dates]
Died: May 2, 1998 (DH36, YL).
Name source: Tom's mother lived long enough to name him 'Tom' after his father, 'Marvolo' after his grandfather (CS13).
Other names: 'Lord Voldemort,' 'You-Know-Who,' 'He Who Must Not Be Named,' 'The Dark Lord,' 'T.M. Riddle' (on diary), 'Tom.' Dumbledore says that Tom began using "Lord Voldemort" a few years after he began his schooling at Hogwarts (HBP13).
Other name meaning: 'Voldemort'= flight from death (French) (JKR).
Name pronunciation: VOL-duh-more (the final 't' is silent, according to JKR in an interview [1]). Film pronunciation: VOL-de-mort.
He-Who-Must-Not-Be-Named: Rowling got the idea for this from two 1950s London gangsters called the Kray Twins. "The story goes that people didn’t speak the name Kray. You just didn’t mention it. You didn’t talk about them, because retribution was so brutal and bloody. I think this is an impressive demonstration of strength, that you can convince someone not to use your name. Impressive in the sense that demonstrates how deep the level of fear is that you can inspire. It’s not something to be admired." (TLC). As soon as Voldemort took control of the Ministry in 1997, he reinforced this fear by putting a taboo on speaking his name. Anyone brave enough to say 'Voldemort' would have their locations immediately revealed to "snatchers" or other enforcement squads who would come and take you into custody (DH).

FAMILY
Ancestry: Half-blood (CS13); descendent of Salazar Slytherin (CS17).
Mother: Merope Gaunt (HBP10), who died in London one hour after giving birth (GF33 & HBP); she was a descendent of Salazar Slytherin (CS17).
Father: Tom Riddle, a Muggle from the village of Little Hangleton who abandoned Merope because he discovered she was a witch (CS13, CS17; GF33); described as anti-magic, rich, snobbish & rude (GF1).
Childhood: 1926-1938, Raised in a Muggle orphanage in London (CS13; GF33, HBP13). Orphanage was clean, but meager: a bare courtyard and grim, square building surrounded by high railings (HBP13). Head matron was Mrs. Cole. Mrs. Cole recalls that he was an odd baby -- he rarely cried, and as he got older he appeared to cause "nasty" things to happen to the other children and to pets around the orphanage. Also stole things: a yo-yo, a silver thimble, and a harmonica ('mouth organ').
Paternal grandfather: Mr. Riddle, also of Little Hangleton.
Maternal grandfather: Marvolo Gaunt, a descendent of Salazar Slytherin (HBP10).
Aunts, Uncles: His maternal uncle was Morfin Gaunt (HBP10).
Siblings: None.
Children: None (WBD2004).
Pet(?): Large snake named Nagini (GF1).
Obsession with his heritage leads to patricide: At Hogwarts, Tom was obsessed with his heritage. Although he knew since his first year that he was the Heir of Slytherin, he didn't learn the complete story until he tracked down and visited his uncle, Morfin Gaunt during the summer of 1943. Morfin told him that his father was a Muggle and his mother was a descendent of Slytherin. At this point, Tom Stunned Morfin and went to Riddle House where he murdered his father and grandparents. Before leaving Little Hangleton, Tom went back to the Gaunt shack and stole the gold Slytherin ring. It is unknown how, but Tom also bespelled Morfin into confessing to the crime. Morfin was convicted for the murders and sentenced to Azkaban (HBP17).
Boggart: "death, ignominious death .... He would see himself dead." (TLC)
Greatest desire: In front of the Mirror of Erised, Voldemort would see "Himself, all-powerful and eternal. That's what he wants." (TLC)

APPEARANCE
As a 16-year-old Tom Riddle: described as having jet black hair (CS13); "tall, black-haired boy" (CS17); "handsome" (CS18); "dark" eyes (HBP).
Distinguishing features: long fingers; high-pitched, cold laugh (CS17).

Voldemort in his late 20s: When Voldemort visited Dumbledore about 10 years after leaving school, he was no longer handsome. His deathly pale face looked "waxy and oddly distorted, and the whites of the eyes now had a permanently bloody look." (HBP20)

Before Wormtail’s rebirthing potion ("baby" form): "had the shape of a crouched human child, except that Harry had never seen anything less like a child. It was hairless and scaly-looking, a dark, raw, reddish black. Its arms and legs were thin and feeble, and its face – no child alive ever had a face like that – flat and snakelike, with gleaming red eyes" (GF32).

After Wormtail’s rebirthing potion: described as "a man, tall and skeletally thin." His face was "whiter than a skull, with wide, livid scarlet eyes and a nose that was as flat as a snake’s with slits for nostrils" (GF32).

"Voldemort looked away from Harry and began examining his own body. His hands were like large, pale spiders; his long white fingers caressed his own chest, his arms, his face; the red eyes, whose pupils were slits, like a cat's, gleamed still more brightly through the darkness" (GF33).

"Unnaturally long fingers" (GF33).

At Battle of the Dept. of Mysteries: "Tall, thin, and black-hooded, his terrible snake-like face white and gaunt, his scarlet, slit-pupiled eyes staring" (OP).

After death: what is left of Voldemort's soul exists as the "flayed baby" Harry saw at King's Cross (BLC).

HOGWARTS
Years: 1938-1945; fees paid by Hogwarts assistance fund (HBP13).
House: Slytherin.
What did Tom know before his first year? Riddle did not know about his heritage, but he had discovered his powers: "I can make things move without touching them. I can make animals do what I want them to do, without training them. I can make bad things happen to people who annoy me. I can make them hurt if I want to." Tom had also discovered that he was a Parselmouth. After Dumbledore told him he was a wizard, Tom assumed that his mother was a Muggle and that he got his magic from his father (HBP13) (see also Voldemort timeline).
When did Tom find out he was the Heir of Slytherin? Tom-in-the-diary (Tom at the end of his 5th year) tells Harry "even I was surprised how well the plan worked. I thought someone must realize that Hagrid couldn't possibly be the Heir of Slytherin. It had taken me five whole years to find out everything I could about the Chamber of Secrets and discover the secret entrance" (CS17). Tom must have discovered he was the heir and that the Chamber existed very soon after his arrival for his first year at Hogwarts.
Artifacts: Diary created in 1943 at the beginning of his 6th year (CS, HBP). Dumbledore noticed that Tom liked to collect trophies: things he had taken from his victims, or stolen outright (HBP13), Slytherin ring, Slytherin locket, Hufflepuff cup (HBP20).
Awards, etc.: Prefect (1942); Medal for Magical Merit; gold shield-shaped award for "Special Services to Hogwarts" kept in the trophy room; Head Boy (1944).
Excelled in studies: According to Dumbledore, "He was one of the most brilliant students Hogwarts has ever seen" (CS18).

AFTER HOGWARTS
After leaving Hogwarts in 1945, Riddle began working at Borgin and Burkes on Knockturn Alley. His job was to ferret out items of value and obtain them at the lowest price possible. He suddenly left this job and disappeared after he killed Hepzibah Smith for a gold locket that belonged to Slytherin and a gold cup that belonged to Helga Hufflepuff (HBP20). Related page: Horcruxes.

WAND, POWERS, ETC.
Wand: yew wood, 13 ½" long, core consists of one of Fawkes’ (phoenix) feathers (PS5). Beginning in 1997, uses a series of wands in an attempt to circumvent Harry's wand:
Skills: Parselmouth (CS), Legilimens (OP24).
Boggart: Death, which he sees as something shameful (TLC).
Major magic:

• Horcruxes to split his soul.
• The "Dark magic" rebirthing potion (unicorn blood, Nagini’s snake venom, bone from his father, flesh from Wormtail, and blood from Harry) (GF32, GF33). Voldemort deliberately used Harry’s blood because he wanted Lily’s "lingering protection" magic in his blood too (GF33).

VOLDEMORT'S MINIONS
Voldemort formed the Death Eaters (formerly the "Knights of Walpurgis") in the ten years after he left Hogwarts. The earliest known members (c. 1956) were Antonin Dolohov, Mulciber, Nott, and Rosier.

Death Eaters and other followers: See the page on the DEATH EATERS

Who is Voldemort's favorite? Voldemort sends others to do his bidding, but he essentially works alone. In Dumbledore's words, "You will hear many of his Death Eaters claiming that they are in his confidence, that they alone are close to him, even understand him. They are deluded. Lord Voldemort has never had a friend, nor do I believe that he has ever wanted one." (HBP13)

On the other hand, Voldemort seems to have an "inner circle" whom he summoned to the Little Hangleton graveyard (GF32) or referred to there as being faithful: Lucius Malfoy, Peter Pettigrew, Avery, Macnair, Crabbe, Goyle, Nott, Bellatrix and Rodophus Lestrange, and Barty Crouch, Jr. (GF32). Severus Snape was also part of this trusted circle (HBP2).

KNOWN VICTIMS
Moaning Myrtle (indirectly by Basilisk), his father & grandparents, Hepzibah Smith, Frank Bryce, Susan Bones' grandparents (BN), Dorcas Meadows (OP9), Lily and James Potter, Bertha Jorkins (Wormtail with Voldemort's wand on Voldemort's orders), Cedric Diggory (Wormtail with Voldemort's wand on Voldemort's orders), Charity Burbage, 'Mad Eye' Moody, Gregorovitch, Gellert Grindelwald, Severus Snape.

SUSPECTED VICTIMS
Amelia Bones (opinion of Cornelius Fudge HBP1).

PROPHECIES
"It Will Happen Tonight."
"The Dark Lord lies alone and friendless, abandoned by his followers. His servant has been chained these twelve years. Tonight, before midnight ... the Servant will break free and set out to rejoin his Master. The Dark Lord will rise again with his servant's aid, greater and more terrible that ever he was. Tonight ... before midnight ... the servant will set out to rejoin his Master..." (Sybil Trelawney, PA16)

The one with the power to vanquish the Dark Lord approaches ...
Born to those who have thrice defied him, born as the seventh month dies ...
And the Dark Lord will mark him as equal, but he will have power the Dark Lord knows not ... And either must die at the hand of the other for neither can live while the other survives. (Sybil Trelawney, OP37)

VOLDEMORT in the FILMS
"Harry Potter and the Sorceror's Stone:" Voldemort (in the flashback) is played by Richard Bremmer; in the Mirror of Erised scene he is voiced by Ian Hart.

"Harry Potter and the Chamber of Secrets:" Tom Riddle is played by Christian Coulson (left).

In "Harry Potter and the Goblet of Fire" and "Harry Potter and the Order of the Phoenix," Voldemort is played by Ralph Fiennes (right).

Footnotes
[1] In an interview with The Orange County Register on 26 October 1999, ("Enchanted with Potter Literature: Fans line up for hours to get their books signed" by Valerie Takahama), Rowling responded this way to the question of pronouncing Voldemort's name:

"Is it Voldemort?" "Or Voldemor?" someone asked about Harry's evil nemesis.
"I say 'Voldemor' but I'm the only one," replied Rowling, pronouncing the name with a silent "t."