As Tom Riddle discovered his muggle inheritance, his hatred towards both his family and magical society increased, leading him to the path of evil and to adopt the moniker Lord Voldemort.
It was around this time that Riddle gave himself the alias 'Lord Voldemort', to spare himself of the reminder of his 'filthy Muggle father', who he later learned had abandoned his wife after learning she was a witch (although in reality he left her after she stopped controlling him with a love potion).
Tom's eyes became permanently bloodshot and his skin grew paler with every murder he committed and with every horcrux he used. By the time he obtained six horcruxes, he was no longer recognizable as Tom Riddle, rather, he had become the Dark Lord Voldemort entirely, through and through.
Christian Coulson is an English actor who portrayed the young Tom Riddle in the film adaptation of Harry Potter and the Chamber of Secrets. He expressed an interest in returning for Half-Blood Prince, but director David Yates felt that he was too old to play the part again, and cast Frank Dillane in the role instead.
Voldemort's eyes post-revival are red, but young Tom's eyes were originally dark brown. When he returned to Hogwarts to ask for the DADA job though (pre-revival, in his own body), his eyes were noted to flash red when he was angry.
Family. Snape's family background is mostly shown in flashbacks during the course of the last three novels. Snape was born to Eileen Prince, a witch, and Tobias Snape, a Muggle, making him a half-blood (hence the name, "Half-Blood Prince").
As Harry said, Dumbledore was the only person who could see right through Tom Riddle. He was already suspicious about what Tom did to the kids from orphanage and later to Myrtle and Hagrid. As one of his teachers, he knew Tom's tendencies toward Dark Arts. And yet he didn't do anything about them.
For the second time in Voldemort's life, the unforgivable curse rebounded on him, as the Elder Wand wouldn't kill its master. Since Harry and his friends had already destroyed all of Voldemort's Horcruxes, this finally ended Lord Voldemort's life, with Harry finally defeating the Dark Lord.
Notably, Voldemort appeared to be entirely unaware of this split, as he later created a seventh Horcrux in his quest to have six, and continued to target Harry Potter despite him now holding part of Voldemort's own soul.
The prevailing theory has been that Voldemort gradually lost his nose (and humanity) throughout his life due to his exclusive use of Dark Magic. The more Dark Magic he tapped into, the less human he became both figuratively and literally. This was only amplified as he split his soul to create the Horcruxes.
Cecilia. Cecilia was a Muggle who was heavily implied to have been Tom's sweetheart. Tom used terms of affection to her and comforted her when she was shocked by Morfin's dead snake. It can be presumed Tom lost her when Merope Gaunt forced him to marry her.
Voldemort is motivated by immortality, superiority, racial cleansing, and more than a bit of self-hatred. Many of these things are shown in earlier books in the series, but become crystallized in the sixth.
Due to his humiliation in the Triwizard Tournament, Cedric eventually becomes a Death Eater and kills Neville Longbottom. Due to Neville's death, the final Horcrux Nagini was never destroyed, and as a result Voldemort is never defeated, kills Harry and takes over the Wizarding World.
During the final battle, Bellatrix was the last Death Eater standing. She was eventually killed in a duel by Molly Weasley after her attempted murder of Ginny Weasley. Before her death, Bellatrix secretly gave birth to an illegitimate daughter named Delphini, whom she conceived with her beloved master, Lord Voldemort.
In Harry Potter and the Deathly Hallows Part 2, Neville is actually the person who destroys Voldemort's last Horcrux in Nagini, rendering him mortal, meaning that he and Harry truly delivered the final blows to Voldemort.
During the series, nope. Early on, Dumbledore knew about how some orphan kid became the most powerful dark wizard ever. But the public at large was ignorant of that fact. Riddle's posse when he went to Hogwarts knew about it, as they became proto-Death Eaters, as they used the name Voldemort between them.
Why does Dumbledore, enigmatic headmaster of Hogwarts, address the sinister Voldemort w/ that invocation? Tom is the muggle name Voldemort was given. His actual official name given to him by his mother was Tom Marvolo Riddle. For Voldemort, this name forever reminds him that he is not a pureblood.
When did Dumbledore realize Tom Riddle was Voldemort?
He saw Tom grow up to become Voldemort, and he was aware of it. Tom had his followers call him Voldemort before he disappeared after being rejected from the Dada position. He was all ready changing his appearance a bit at that time. So when Voldemort returned, Dumbledore all ready knew who he was.
By Harry Potter and the Deathly Hallows, it's a stretch to call Draco a villain anymore. We just watched — or read — him struggle to reconcile his choices and morals in The Half-Blood Prince. He can no longer justify his actions, and is far more aware of the evil he was born and raised into.
To protect his Horcrux, Tom Riddle placed the ring under a very powerful curse, so much so that Albus Dumbledore himself mentioned that had it not been for his prodigious skill, he might have died in mere moments of being cursed.
Under the influence of her father, Dolores grew up despising her mother and brother for their lack of magical abilities. She was sorted into Slytherin House at Hogwarts School of Witchcraft and Wizardry and hated her time at the school due to never being given any positions of power.
