“Game of Thrones” Season 5 isn’t going well for Cersei Lannister (Lena Headey). Her 15-year-old son, Tommen (Dean-Charles Chapman), married Margaery (Natalie Dormer); her father is dead; and her brother/lover Jamie (Nikolaj Coster-Waldau) is away on a mission to get their daughter Myrcella (Nell Tiger Free) back. However, trouble is still on the way for Cersei. There are new characters who want her to suffer: the Sand Snakes.

Readers of “A Song of Ice and Fire” know that the Sand Snakes are Oberyn Martell’s (Pedro Pascal) eight illegitimate children. It looks like the show will introduce only three of them in episode 4: Obara (Keisha Castle-Hughes), Nymeria (Jessica Henwick) and Tyene (Rosabell Laurenti Sellers). After their father’s bloody death last season, the girls are ready for revenge.

“The details don't matter to them at all,” Castle-Hughes revealed to the Hollywood Reporter. “It's totally an eye-for-an-eye mentality. You hurt my family, now I hurt yours. They are gunning for whatever Lannisters are left.”

According to the synopsis for episode 4, the girls will “vow vengeance” on their father's death, along with Ellaria (Indira Varma), Oberyn’s lover. Ellaria made it clear in episode 2 that she wasn’t happy that Myrcella Lannister was being kept safe with Oberyn’s family. If the women really are on “on a crusade for the downfall of the Lannisters,” as Castle-Hughes said, Myrcella might be the easiest target.

If they do go after the young Lannister, they won’t immediately succeed. As previously reported, Myrcella will take on a larger role this season. She’ll get quite a bit of screen time in "Game of Thrones" Season 5, episode 6 when she and her fiancé Trystane Martell (Toby Sebastian) spend some time together. Trystane might not despise the Lannisters as much as his cousins.

“Trystane really is just in his own little bubble, caught up in his world with Myrcella,” Sebastian told Hunger TV. “A world, which, as far as an arranged marriage goes, is the best-case scenario.”

However, Trystane won’t be able to protect all of the Lannisters from the Sand Snakes. It isn’t clear who their target will be, since "Game of Thrones" is making changes and going beyond the timeline of the books. But viewers should expect any attacks to be brutal because the girls are trained warriors. “They never fight as individuals. They fight together and love to fight,” Castle-Hughes told HBO.

Learn more about the Sand Snakes below:

“Game of Thrones” Season 5, episode 4 airs Sunday at 9 p.m. EDT on HBO. Do you think the Sand Snakes will actually get to the Lannister family, or will they die trying? Sound off in the comments section below!