Oberyn Martell

Younger brother of Prince Doran Martell, Oberyn studied at the Citadel, took up with the sellsword companies of Essos, and learned to mix a poison as smoothly as a cup of wine. He kept paramours in every port and left the Sand Snakes behind him — the bastards Dorne half-feared and half-adored, and the reason his brother spent the rest of his life apologising for him.

His sister Elia and her children were killed in the Sack of King's Landing, and the Mountain's hands on their bodies made it a debt Dorne never stopped counting. Oberyn spent thirty years looking for a man with proof against the Lannisters — and found Tyrion standing accused of a murder he did not commit, and a trial by combat with Gregor Clegane's name already written on it.

He fought the Mountain with poisoned spear and righteous fury, and had the confession he wanted half-said when the bigger man took him in his hands and broke him. The Red Viper died seconds from the finish, and the war he had wanted for Dorne began anyway, thirty years late.