Tyene Sand

Tyene Sand was a bastard daughter of Prince Oberyn Martell and his paramour, Ellaria Sand, and one of the Sand Snakes. She takes part in the Coup in Dorne, during which she seizes power in Dorne from the legitimate House Martell along with her mother, Ellaria, and her half-sisters Obara Sand and Nymeria Sand, by murdering Myrcella Baratheon, Doran Martell and Trystane Martell. She is later poisoned by Cersei Lannister for her role in Myrcella's murder.