Lord Voldemort is the adult form of Tom Riddle. Tom Riddle was placed in Slytherin house on his first Hogwarts day. AS a young child that was orphaned, Tom enjoyed stealing things from other muggle children ( lived in a muggle orphanage). When Albus Dumbledore came to visit him, he told Tom about how he was a wizard and how to control magic. "Did you know," Harry Potter asked Dumbledore, with Dumbledore replying no, he did not know he had just met the most dangerous dark wizard of all time. As Riddle grew up, he took the name "Lord Voldemort" which is an annagram of the name Tom Marvolo Riddle, as reveled in the Chamber of Secrets (Tom Marvolo Riddle changing into I AM LORD VOLDEMORT). In the Half-Blood Prince, new things are discovered about Voldemort's sad, dark, lonely childhood. It seems Voldemort's ultimate goal was to kill someone after he failed to do so, in this case, Harry Potter.