Harry Potter: 10 Best Characters Introduced After The Philosopher's Stone

Getting Jim Broadbent into this series was not only a spark of genius but also an inevitability. He's tailor-made for the Wizarding World, and that could clearly be seen in his performance as Horace Slughorn, the eccentric yet troubled professor who unwittingly became responsible for Voldemort's rise to near immortality.

Introduced in The Half-Blood Prince, Professor Horace Slughorn came along to take over the position of Potions Master at Hogwarts. But, this was simply a ploy from Dumbledore to find out about his past with Tom Riddle and how he taught him about Horcruxes.

The character was a lot of fun, as he played to those stereotypes of tenured professors favouring only the most exceptional students, but in the literal sense that he enjoyed "collecting" them. This gave him a general sense of snobbery but also frivolity thanks to his lavish dinner parties.

Still, it was his dark side that made him even better. His conflict over his past with Tom Riddle was clear from how hesitant he was to bring it up, and this reserved nature made him very three-dimensional.