Merlin series 3

The third series of Merlin began on 11 September 2010. Series three regular cast members include Colin Morgan, Bradley James, Katie McGrath, Angel Coulby, Anthony Head, and Richard Wilson, as well as Emilia Fox joining the regular cast. John Hurt took his previous role as the voice of the Great Dragon but was no longer one of the regular cast (though he continued to provide the opening narration for the series). Series three consists of 13 episodes. The series three premiere was watched by 6.49 million viewers.

Series 3 introduced the format of a two-part opener and two-part finale, this format was retained for Series 4 and Series 5. The series was notable for the change in character of Morgana from the sympathetic heroine in the first two series to the villain in series 3, keeping with the historical concept of Morgana as Merlin's nemesis in the legends of King Arthur. BBC officially renewed the show for series 4 on 10 October 2010.

Plot
Camelot rejoices as the Lady Morgana is found and returned home, however not all is at it seems for Merlin, as he soon learns that Morgana has changed for the worse. Now in league with Morgause, Morgana's powers begin to grow and she becomes a deadly enemy within the walls of Camelot, but with Uther and the kingdom blind to her treachery, can Merlin thwart her plans before she can destroy Camelot?

Loyalties are tested to the limit as a dangerous game is played for the throne. Old friends return to the kingdom, and new enemies grow stronger outside the walls of Camelot. Merlin must be more alert than ever if he is to protect Prince Arthur, for his greatest enemy is now within the castle walls....Morgana. As the King's loving ward plays her game of lies and manipulation, can Merlin stop Morgana before Camelot is lost forever, or is the kingdom set to crumble under the force of secrets and lies?

Main cast

 * Colin Morgan as Merlin
 * Angel Coulby as Gwen
 * Bradley James as Arthur
 * Katie McGrath as Morgana
 * Anthony Head as Uther Pendragon
 * Richard Wilson as Gaius

Recurring

 * John Hurt as the Great Dragon (voice)
 * Emilia Fox as Morgause
 * Rupert Young as Sir Leon
 * Eoin Macken as Gwaine
 * Adetomiwa Edun as Elyan
 * Michael Cronin as Geoffrey of Monmouth
 * Tom Ellis as King Cenred
 * Alice Patten as Ygraine

Guest stars

 * Mark Williams as the Goblin (voice)
 * Karl Johnson as Taliesin
 * Miriam Margolyes as Grunhilda
 * Georgia King as Elena
 * Simon Williams as Lord Godwyn
 * Warwick Davis as Grettir
 * Donald Sumpter as the Fisher King
 * Pauline Collins as Alice
 * Eddie Marsan as the Manticore (voice)
 * Harry Melling as Gilli
 * Ralph Ineson as Jarl
 * Laura Donnelly as Freya
 * Santiago Cabrera as Lancelot
 * Tom Hopper as Percival