Muggles' Guide to Harry Potter/Characters/Tom Marvolo Riddle

Overview
Tom Marvolo Riddle, the only child of the Muggle Tom Riddle and witch Merope Gaunt, attended Hogwarts some fifty years before the story opens. He was born on 31 December; internal evidence in the series indicates that this would have fallen in the late 1920s, some sources indicate that he was born in 1926.

Chamber of Secrets
A secret diary, originally belonging to Tom Riddle, plays an important part in the plot. Through magic embedded in it, Riddle's memory bewitches Ginny Weasley into opening the Chamber of Secrets and releasing a monster that attacks Muggle-born students. When Ginny becomes frightened by the diary's power, she throws it away. Harry happens upon it, and the diary shows him a day fifty years before, when Rubeus Hagrid was accused of opening the Chamber and releasing the monster. Later, with the diary back in Ginny's possession, Riddle's memory summons her to the Chamber of Secrets; there he begins draining her life force to restore his own body. Harry kills the monster, then destroys the diary, vanquishing Riddle's memory, and saving Ginny's life. Harry discovers the diary had been surreptitiously slipped to Ginny by Lucius Malfoy.

During the battle inside the Chamber of Secrets, Tom Riddle is revealed to be the same person as Lord Voldemort.

Goblet of Fire
Tom Riddle's name never appears, though it can be inferred: Tom Riddle of Riddle Manor, who we deduce is Tom Marvolo Riddle's father, is mentioned as having been found incomprehensibly dead along with his parents some fifty years before. Riddle Manor, the house in Little Hangleton, plays a part in the story.

Order of the Phoenix
During the duel between Albus Dumbledore and Voldemort at the Ministry of Magic, Dumbledore repeatedly calls his opponent "Tom", much to his annoyance.

Half-Blood Prince
Dumbledore tells Harry they will be having private lessons throughout the year. Harry, intrigued, wonders what special magic Dumbledore will teach him, but is surprised by the first session; it seems they will be studying Tom Riddle as he grew up. By watching memories in Dumbledore's Pensieve, Harry (and thus the reader) becomes acquainted with Lord Voldemort's origins and why he discarded his birth name, Tom Marvolo Riddle. Professor Dumbledore always refers to him by this name, even when he is calling himself Voldemort.

Tom is never seen as an infant, but we see his mother, Merope, uncle Morfin, and grandfather, Marvolo Gaunt at their ramshackle house. Merope has become infatuated with the handsome Muggle, Tom Riddle. Shortly after Marvolo and Morfin were arrested and imprisoned, the homely Merope eloped with Riddle. Dumbledore suggests she possibly used a love potion to coerce him into marrying her, but may have stopped using it after becoming pregnant, perhaps believing that bearing his child would keep him with her. Tom Riddle quickly abandoned Merope and their unborn offspring.

Tom Marvolo Riddle, Merope Gaunt's son, is first seen in the orphanage where he grew up. Dumbledore has arrived to offer the 11-year-old boy admission to Hogwarts. Discussing Tom with the orphanage matron, Dumbledore learns that Merope passed away shortly after giving birth one New Years' Eve; she asked that her son be named Tom, after his father, and Marvolo after his grandfather. Tom, a quiet and withdrawn boy, apparently lacked friends. Strange things happen around Tom, but nothing directly caused by him; he also frightened the other orphans. On the annual seaside outing, two children were terrified by something to do with a cave, but neither would discuss it. In Dumbledore's memories, Tom appears assured far beyond his years, though he remains a solitary figure. He is initially suspicious when Dumbledore visits, believing he may be a doctor from a psychiatric hospital, but is won over by Dumbledore displaying magic. Interestingly, Tom seems bothered when Dumbledore mentions that someone named Tom works at the Leaky Cauldron. Tom dislikes his name, for some reason. Almost as an afterthought, Tom mentions he can talk with snakes.

Dumbledore says few memories still exist concerning Tom Riddle's school years; those who do remember Tom are reluctant to discuss him. One memory belongs to Tom's uncle, Morfin Gaunt. Morfin evidently believed that Tom, now grown, was his father, Tom Sr., and it was only after Tom spoke in Parseltongue that Morfin realized he was Merope's son. Tom then apparently Stunned Morfin, stole the Gaunt signet ring and Morfin's wand, then killed his Muggle father, Tom Riddle, Sr., and his father's parents. Morfin's memory was modified so that Morfin recalled killing the Muggles, and forgot Tom's presence.

Tom is seen in a memory belonging to Professor Slughorn. Tom, wearing the Gaunt ring, is among his school cronies, then later asks Slughorn about Horcruxes. In this memory, which Dumbledore says is obviously edited, Slughorn claims he knows nothing about Horcruxes. Dumbledore tells Harry that obtaining the original memory is crucial, and he alone is uniquely equipped to retrieve it. If he fails, Dumbledore's lessons will be useless.

Another memory belonging to a house-elf, Hokey, shows Tom, who now works for Borgin & Burkes, as he calls on an elderly but vain witch, Hepzibah Smith. Taken with Tom's charm, she shows him her most treasured items: Salazar Slytherin's locket, and Helga Hufflepuff's cup. Greed and suppressed anger at seeing the locket swell up in Tom, who apparently remembers Morfin Gaunt telling him that Merope took it with her when she left. Hepzibah died soon after Tom's visit, apparently accidentally poisoned by Hokey; her two treasures had vanished.

In another memory, Tom is applying for the post as Hogwarts' Defence Against the Dark Arts instructor. Then-headmaster Dippet turned him down, saying he lacked real-world experience. In Dumbledore's own memory set some years later, Tom is again refused the position, this time because Dumbledore distrusts Tom to teach the subject. Dumbledore notes Tom's changed appearance, and knows he now calls himself Voldemort, though he still addresses him as Tom. Dumbledore is also aware that Tom's supporters have accompanied him to Hogsmeade.

Some time later, Harry secures Slughorn's unedited memory. In response to Tom's questions, Slughorn responds that a Horcrux is among the darkest things in Dark magic. Murdering someone tears the soul; with incantations, which Slughorn professes not to know, a torn-off soul fragment can be encapsulated into another object, which is a Horcrux. The Horcrux binds the soul to earth when the body housing it is killed. Tom then asks, if one Horcrux can give immortality, would more not be better? Is not seven the most magical number? Slughorn is horrified by this suggestion; Tom claims it is purely an academic question, but Harry notes his triumphant expression, similar to the one Tom had when Dumbledore told him he was a wizard.

Dumbledore reveals that the diary in Harry Potter and the Chamber of Secrets was one of Tom's Horcruxes. It allowed Riddle's memory to think and act independently and to nearly become a material person by sapping Ginny Weasley's life force. Discovering this worried Dumbledore, as Horcruxes would normally be kept safely stored and hidden, and yet the diary seemed crafted as a weapon, in addition to a means of immortality. Dumbledore feels certain that this would not have been done if it had been the only Horcrux Tom had made; with this memory, he understands that Tom, or Voldemort, would have made six Horcruxes, leaving a total of seven soul fragments. Two, the diary and the Gaunt ring, have been found and eliminated, likely leaving four more. When he finds another, Dumbledore says Harry can accompany him to help retrieve and destroy it.

Dumbledore surmises that Tom only used significant objects to craft his Horcruxes, including ones tied to his heritage. The Gaunt ring, for instance, is an ancient family heirloom, as is the Slytherin locket. Dumbledore explains the diary's importance, saying that it having been used to open the Chamber was proof that Tom is the heir of Slytherin. Dumbledore suggests further that, even as the Horcruxes were made from significant items, they will also be hidden in particularly significant places. The ring was found in the Gaunt shack, for instance.

Dumbledore summons Harry to his office one final time, telling him he has located the sea cave where Tom took his two young victims from the orphanage. Dumbledore believes that, as this was where Tom's earliest triumph took place, it is extremely likely a Horcrux is hidden there. Tom had, in fact, concealed a Horcrux there, though an as-yet unknown person found and removed it later.

Deathly Hallows
Slytherin's locket, mentioned in Harry Potter and the Half-Blood Prince, is recovered and proves to be a Horcrux, as expected. Harry finally manages to open it. It is mentioned that the eyes in the locket Horcrux are Tom Riddle's handsome eyes, from before he changed his appearance to its current snakelike state.

While his name is not mentioned explicitly, Harry learns that Tom once charmed the Grey Lady, who is the ghost of Rowena Ravenclaw's daughter, into revealing where Ravenclaw's lost diadem was hidden. Having then retrieved the diadem, Tom had converted it into a Horcrux and hidden it in the Room of Requirement.

When Harry is dueling Voldemort, Harry addresses him as "Tom" or "Riddle", to show he rejects the power of Riddle's "new" name.

Just after he dies, the text says that "Tom Riddle hit the floor".

Strengths
Tom is an extremely powerful wizard, intelligent, ambitious and resourceful. Even before receiving any training, he is able to produce somewhat-controlled magic, without using a wand. He is also able to perform NEWT-level magic, probably before he has even completed his OWLs.

In Hokey's and Horace Slughorn's memories, we learn that Tom, a handsome lad, can be extremely persuasive and charming, traits he often uses to gain an advantage. His charismatic personality attracts and retains followers to his inner circle, though he never considers anyone as a "friend".

Weaknesses
Professor Slughorn's memory shows that even as a teen-aged boy, Tom was already so consumed with his own immortality that he had created a Horcrux. (Evidence in the series indicates that the Gaunt ring was made into a Horcrux on the same night it was stolen from his maternal uncle, Morfin; thus, when it was seen on Riddle's hand in that memory, it was already a Horcrux.) This would indicate that he deeply feared death.

In Dumbledore's memories, we see that Tom Riddle was always very much alone, apparently preferring it that way. He had no companions at the orphanage, and refused any assistance, other than funds, with buying his school supplies in Diagon Alley. This determination to do everything himself, which he likely perceives as strength, actually masks a major weakness, an inability to understand how other peoples' minds truly work. Also, he, unlike Harry Potter, failed to realize that to succeed in anything, you must have loyal allies. He also lacks any capacity to love, resulting in his having no friends, loved ones, or family from which he can derive strength and comfort.

Relationships with Other Characters
Tom always appeared to be a solitary figure, usually preferring his own company. At the orphanage he has no friends as the other children feared him, and at Hogwarts he gathered followers, not schoolmates, though he treated them like friends in public. Even at this young age, those who gravitated to Tom seemed mostly interested in gaining something, rather than befriending him, and perhaps feared reprisals if they left. Tom never considered anyone, ally or enemy, worth his respect, and only trusted himself.

Tom had no interest in or loyalty to his immediate family, killing every one he met, including his Muggle father, paternal grandparents, and maternal uncle. Although his father abandoned him and his mother, his other relatives never inflicted any harm on Tom, though this had no effect on his decision to murder them. Any feelings he may have had for his late mother are unknown, though he despised his father for having deserted her. Probably the only one Riddle did admire was Salazar Slytherin, his ancient ancestor.

It is said that the only person Lord Voldemort ever feared was Albus Dumbledore. This fear probably started with Dumbledore's display of magic before Tom in the orphanage, and was not dimmed over the years, despite Tom's having assumed the new name.

Tom seemed to have some degree of respect for his Head of House, Horace Slughorn, though it's likely that this was merely a form of flattery in order to get information. Nonetheless it is implied that he at least recognized that Slughorn was a talented and knowledgeable wizard, shown by his certainty that the professor would have the information he needed about Horcruxes.