'Game Of Thrones' Trailer: Who Is The Red Viper?

Prince Oberyn Martell of Dorne appears in the upcoming season of 'Game of Thrones,' but who is he, and why should you care? Find out now!

"Tell your father I'm here, and tell him the Lannisters aren't the only ones who pay their debts."

Those chilling words come courtesy of Prince Oberyn Martell of Dorne, one of the new characters set to make his debut on the coming season of "Game of Thrones." HBO premiered its first full trailer for season four on Sunday night, and Oberyn, played by Chilean actor Pedro Pascal, was all over it — but if you're not familiar with the novels that "Thrones" is based on, perhaps you missed him, or you just want to know more.

In either event, you're in luck. Here's what you need to know about Oberyn before the new season of "Thrones" begins:

1. He hails from Dorne, all the way in the south of Westeros. We've heard much of Dorne throughout the first three seasons of "Thrones," usually when someone sings the praises of the city's wine and women. But that's not to speak of their highly trained soldiers, of course, and Prince Oberyn is right at the top of that heap.

2. His name is Oberyn, but everyone calls him the Red Viper. Why do they call him that? For one, it's a badass name, fitting for a badass dude. For another, it's rumored that when he was 16, he fought and killed a challenger by using a poison-tipped blade. In Westeros, it's said that poison is a woman's weapon, but Oberyn has found a way to make it work for himself just as well.

3. He has children. Lots and lots of them, in fact. In the "A Song of Ice and Fire" novel series, the Red Viper has no fewer than eight bastard daughters, referred to as the Sand Snakes. They're said to be almost as deadly as daddy dearest, and all of them are up to their own schemes and devices — a fact we're sure to see for ourselves as "Thrones" pushes beyond its fourth season.

4. He has history, with the Lannisters specifically. When Tywin Lannister's forces wrested King's Landing away from Aerys Targaryen, they brutally beat and killed the Mad King's family. That included Oberyn's sister, Elia, who was married to Prince Rhaegar Targaryen at the time. It's said that Gregor "The Mountain" Clegane killed Elia's children before right in front of her, and killed her moments later. Needless to say, that didn't sit well with Oberyn.

5. He has a purpose. It's no mere coincidence that Oberyn Martell is suddenly in King's Landing this coming season. He put himself directly on the Lannisters' path, because it's time to seek what's rightfully his: Vengeance for the murder of his sister, nephew and niece. With poison-tipped weapon in hand, and a cold vendetta in his heart, there's nothing that can stand between Oberyn and justice — nothing, save for a little old Mountain.

What do you make of Oberyn Martell, the Red Viper of Dorne?