Knight of High Hermitage and head of a cadet branch of House Dayne, a handsome man with thick silver hair cut by a streak of midnight black and dark purple eyes, jealous of his cousin Ser Arthur Dayne who carried Dawn before him. He counts himself of the night where Arthur was of the morning, and the lords of Dorne reckon him a viper among vipers; Prince Oberyn himself was said to have named him poison and to have regretted only that he never got around to killing him.
He was for a time numbered among Princess Arianne Martell's lovers, and she brought him into the conspiracy to crown Princess Myrcella Baratheon at Shandystone in place of her brother King Tommen, for his sword and for his keep, by her own admission, and for nothing else. When Areo Hotah ran the plot to earth at the Greenblood, Darkstar struck at Myrcella as her party surrendered; her horse reared and his blade took only her ear and the side of her face before he broke away into the sands. He keeps still to High Hermitage, with Obara Sand and Ser Balon Swann sent by Prince Doran to bring back his head.