Asha Sand is the youngest of Prince Calon Martell's bastard children, mothered in secret by his third and final paramour, Viserra Targaryen. She is currently residing at Sunspear with her father and siblings.
In order to protect Asha and her mother, upon her birth, Calon Martell allowed rumors to spread around Sunspear and beyond that the girl's mother was a Dayne. The rumor swept through the court and through the lords of Dorne, more effectly than the Prince could have hoped. As a result, Asha's true lineage remains unknown by all to this day, with the exception of her parents, Calon's wife Dorea Yronwood, and a few of her Martell relatives.