Game of Thrones employs one of the largest casts in television, but it will be getting even larger in the upcoming fourth season.
The Game of Thrones writers will be adapting the second half of A Storm of Swords, the third novel in George R. R. Martin's A Song of Ice and Fire book series. In this section of the book, there are several new characters introduced that will play a big role in several main plots.
MAJOR BOOK SPOILERS AHEAD:
One of the most important new characters introduced is Prince Oberyn Martell, who is nicknamed The Red Viper. Martell, who will be played by Pedro Pascal, is a young warrior who secretly conspired to put an end to Robert Baratheon's reign and bring down the Lannisters. He returns to King's Landing to seek answers about his sister's death.
After Tyrion (Peter Dinklage) is accused of murder, The Red Viper elects to serve as his stand-in for the ensuing trial by combat. In exchange, Tyrion tells him the truth behind his sister's murder. Unfortunately, the prince is unable to defeat The Mountain in the trial by combat and dies.
Another big character expected to debut in season 4 is Mace Tyrell, played by Roger Ashton-Griffiths. Mace Tyrell is the father of Margaery (Natalie Dormer) and Loras (Finn Jones). Mace comes to King's Landing for the wedding of Margaery and Joffrey (Jack Gleeson) and serves as one of the judges in Tyrion's trial.
Some of the roles that have been recast for season 4 include Daario Naharis, who was originally played by Ed Skrein but will now be played by Michiel Huisman. Meanwhile, Dean-Charles Chapman is taking over the role of Tommen Baratheon, who becomes the new King in the wake of Joffrey's death.
Game of Thrones season 4 premieres in spring 2014 on HBO though the network has not yet announced a specific start date.