Sarella Sand is one of the famous Sand Snakes, the bastard children of Oberyn Martell. Her mother was a trader captain from the Summer Islands. She is nearly twenty years old, and has a reputation for insatiable curiosity and "pushing in where she didn’t belong".
When Doran Martell orders Areo Hotah to take the Sand Snakes into captivity, Sarella is outside of Dorne. Doran says that he prays she will show more sense than her sisters, and tells Areo to "leave her to her game"