Unlike his sickly and pensive brother, Oberyn is notorious for both his dangerous and unpredictable nature and his affinity for poisons, for which he earned his nickname.

Though Oberyn manages to gain the upper hand in the duel and impale Clegane to the ground with his spear, Clegane manages to surprise him by foot sweeping him to the ground and bear-hugging him, then gouging his eyes and finally killing him by repeatedly smashing his unarmored face (Oberyn is wearing a light visorless halfhelm) with a mailed fist.

[2] However, it is later revealed that Oberyn has coated his spear in manticore venom to ensure that Clegane will die a slow and agonizing death.

When news of Oberyn's death reaches Dorne, the oldest three Sand Snakes Obara, Nymeria and Tyene unsuccessfully attempt to pressure Prince Doran into declaring war against the Iron Throne.

The three Sand Snakes are later also told about the plan, released after swearing allegiance to Doran's strategy, and assigned individual missions to infiltrate the Iron Throne as sleeper agents.

Oberyn Martell is played by Chilean-American actor Pedro Pascal in the fourth season of the HBO television adaptation.

[3][4] Oberyn arrives in King's Landing with his paramour, Ellaria Sand, to attend Joffrey's wedding in his brother's stead, and his meeting with Tyrion makes it clear that he has actually come to take revenge against the Lannisters for their role in the deaths of his sister, nephew and niece.

Tyrion is subsequently sentenced to death, but Oberyn's objective of vengeance was not in vain, since his spear is revealed to have been laced with the deadly venom of the manticore, which later begins to kill Clegane.