6. Radagast The Brown Sets Up LOTR Events
Despite only being mentioned once in The Hobbit text, Radagast the Brown - a fellow wizard of Gandalf's (who is actually mentioned as his cousin in The Hobbit) - plays an important, expanded part in the film adaptation. He is shown as a resident of Greenwood the Great (later to be known as Mirkwood), who looks after animals and can control them thanks to his powers: somewhat foolish, he is nevertheless powerful and he stumbles upon the presence of the Necromancer in the castle ruins of Dol Guldur, who has power over the dead, and who accidentally allows Radagast to take an ancient relic of Mordor as proof of his existence to Gandalf. That sets in motion the wheels that will eventually lead to the discovery of the Necromancer as Sauron, and the White Council's intervention to drive him from Mirkwood, which was originally set about by Gandalf's own exploration of Dol Guldur in Tolkien's texts and his reporting to the White Council. The details are changed slightly to include Radagast in order that the Necromancer's story, which is told in the LOTR Appendices can run concurrently with the main events taken from The Hobbit, and so Gandalf didn't have to be in two places at once. It's a good expansion, all told, and Sylvester McCoy's take on the character is very good, if a little odd, and the presence of the Necromancer adds further darkness and drama to The Hobbit's main adventure.