Voldemort

Hagrid tells Harry the basics: Voldemort gathered followers, spread terror and killed anyone who got in his way. The night he went after the Potters, the Killing Curse he cast at the baby turned back on him. Since then he's lived as a shadow, with no body of his own.

During Harry's first year, Voldemort is hiding inside the castle. In the Forbidden Forest, a hooded figure drinks unicorn blood to stay alive. In the end, Harry discovers that Professor Quirrell carries Voldemort's face on the back of his head, hidden under his turban. The goal is the Sorcerer's Stone, which would give him a body and the Elixir of Life. Quirrell can't touch Harry without burning, because of the protection Harry's mother left him, and crumbles away. Voldemort's spirit escapes by passing through Harry.

Harry finds a diary that belonged to Tom Marvolo Riddle, a Hogwarts student 50 years earlier. The diary writes back when Harry writes in it and shows him a memory: Riddle accusing Hagrid of opening the Chamber of Secrets. It was a lie.

In the Chamber, Riddle appears in person, young and growing more solid while Ginny Weasley weakens on the floor. He writes his name in the air and rearranges the letters: "I am Lord Voldemort." He was the Heir of Slytherin, the one who opened the Chamber the first time and the one who used Ginny to open it again. He sets the basilisk on Harry, who kills the snake with the sword of Gryffindor and drives the fang into the diary. Riddle dissolves.

In the abandoned Riddle house, Voldemort, still weak and in a small, twisted form, makes plans with Wormtail and Barty Crouch Jr. and kills the old caretaker who overheard them. Harry sees it in a dream.

The Triwizard cup takes Harry and Cedric Diggory to a graveyard. Voldemort orders Wormtail to "kill the spare," and Cedric dies. In a cauldron, Wormtail combines the bone of Voldemort's father, his own severed hand and Harry's blood, and Voldemort has a body again: bald, pale, noseless. He touches the Dark Mark on Wormtail's arm and the Death Eaters Apparate around him. Voldemort scolds them for their lack of loyalty and challenges Harry to a duel. The two wands lock together with a thread of light, and echoes of Voldemort's victims pour out of his wand. Harry escapes with Cedric's body.

Voldemort prefers to work in the shadows while the Ministry denies he's back. The imprisoned Death Eaters break out of Azkaban, Bellatrix Lestrange among them. Voldemort wants the prophecy kept in the Department of Mysteries, which concerns him and Harry, and he learns that there's a link between their minds. He uses it to plant in Harry a vision of Sirius being tortured and lure him to the Ministry.

The prophecy shatters in the fight. Voldemort appears in the atrium, duels Dumbledore and, losing, enters Harry's mind and tries to use the boy's body. He can't stand what he finds there and pulls out. Minister Fudge arrives in time to see him before he vanishes, and the wizarding world finally admits the truth.

In the Pensieve, Dumbledore shows Harry the boy Tom Riddle at the orphanage where he grew up. Tom can already move things without touching them, frightens the other orphans and keeps stolen objects as trophies. When he learns he's a wizard, he loves finding out he's special.

Another memory shows Riddle as a teenager, a brilliant student and Horace Slughorn's favorite, asking about Horcruxes. Slughorn had tampered with that memory out of shame. In the real version, he explains that a Horcrux holds a piece of the soul, split off through murder, and Riddle asks what would happen with seven. Dumbledore understands the plan: Voldemort scattered his soul into objects so he couldn't die. The diary was one of them, and the ring Dumbledore destroyed was another. Meanwhile, Voldemort orders Draco Malfoy to kill Dumbledore.

At Malfoy Manor, Voldemort gathers the Death Eaters, kills Professor Charity Burbage in front of them and feeds her to Nagini. He takes Lucius Malfoy's wand so he can kill Harry personally, since his wand and Harry's can't duel each other. In the chase across the sky, Harry's wand acts on its own and the borrowed wand is destroyed.

The Ministry falls to the Death Eaters, and Voldemort's name becomes a taboo that gives away the location of anyone who says it. He hunts for a more powerful wand: he questions the wandmaker Gregorovitch and an old prisoner in Nurmengard. At the end of the movie, he opens Dumbledore's tomb at Hogwarts and takes out the Elder Wand.

Voldemort feels it when his Horcruxes are destroyed and surrounds Hogwarts with his army. Suspecting the Elder Wand doesn't fully obey him, he concludes it belongs to Snape and orders Nagini to kill him. Then he offers a truce: Harry must give himself up in the Forbidden Forest. Harry goes, and Voldemort casts the Killing Curse. Both of them fall. Narcissa Malfoy says Harry is dead, and Voldemort parades the body in front of the castle's defenders.

Harry was alive. Neville Longbottom kills Nagini, the last Horcrux, with the sword of Gryffindor. In the final duel, the Elder Wand refuses to kill its true master, who is Harry, and flies into his hand. Voldemort breaks apart into flakes that drift away into the air.

In the books, Voldemort has red eyes with slit pupils like a cat's and a snakelike face; the movies left Ralph Fiennes's eyes as they are and erased his nose digitally. J.K. Rowling has said the final "t" in the name is silent, French-style, even though everyone in the movies pronounces it. The books spend far more pages on memories of his family, the Gaunts, which the movie left out.