On tonight's Game of Thrones Season 4 premiere, fans are going to meet Oberyn Martell, AKA the Red Viper, played by Pedro Pascal. But who is Oberyn Martel, and what can we expect from him?l? We've got the rundown, based on the A Song of Ice and Fire book series.

Warning: This article contains spoilers from the A Song of Ice and Fire book series. Click away now if you don't want to know!

Oberyn Martell is a prince of Dorne, known widely as a great warrior, potentially bisexual lothario, and exotic world-traveller. He’s clearly got a lot going for him, but to understand where he comes from, we need to go over a little history on Dorne, since Oberyn is the first Dornishman we’ll have the pleasure of meeting in the series.

Dorne is one of the Seven Kingdoms of Westeros, and it’s where Joffrey’s sister Myrcella was sent by Tyrion in Season 2, to be betrothed to a prince of the Martell family. The Martells run the show in Dorne, like the Lannisters do in the West or the Starks do (er, did) in the North. Dorne also has the distinction of being the only one of the Seven Kingdoms that was never conquered by the Targaryens; they joined the Seven Kingdoms much after the others through diplomatic means. As a result, Dorne has maintained its own distinct culture. It’s a hot, desert climate, and its people have olive skin and dark features. The heirs of the Martell family also use the titles prince and princess as opposed to lord and lady like the rest of the Seven Kingdoms. Dorne has thus far taken no (direct) part in the War of the Five Kings.

In A Song of Ice and Fire, Oberyn is sent to King’s Landing to act as a member of the small council, as part of the deal that sent Myrcella to Dorne. This move was done in hopes of securing Dorne to Joffrey’s side in the war. However, the Dornish have other plans. When Oberyn shows up, he says he’s really come for justice. See, way back during Robert’s Rebellion, Rhaegar Targaryen’s wife was Ellia Martell, Oberyn’s sister. She was raped and murdered, along with her two small children, by the Hound’s brother, Gregor Clegane, when the Lannisters sacked King’s Landing. The Red Viper knows this, and he wants those guilty brought to justice.

Eventually, The Red Viper gets his chance for revenge when he faces Gregor Clegane, AKA The Mountain That Rides, in single combat. It’s one of the most thrilling scenes in the books, and should make for great television. The Mountain has been seen sparingly in the TV series thus far, and has even been portrayed by two different actors. The fight is his biggest and most important scene of the books, so let's hope Pedro Pascal can do it justice.

Are you looking forward to Oberyn on the show? Sound off in the comments below!