Gerold Dayne, nicknamed Darkstar, is the Dayne knight who appears in the novels but not in Game of Thrones.
Gerold is a dangerous member of House Dayne and a distant relative of the legendary Ser Arthur Dayne. He is known as Darkstar because of his striking appearance and his reputation for violence. Unlike Arthur, who is remembered as an honorable Kingsguard knight, Gerold is associated with ambition, cruelty, and instability.
In the novels, Gerold becomes involved with Arianne Martell’s attempt to crown Myrcella Baratheon. During the escape from the failed plot, he slashes Myrcella’s face, leaving her disfigured, and then flees. His disappearance creates an unresolved thread: Arianne later seeks him, while Gerold claims that he was falsely accused of trying to kill the princess.
Darkstar is often confused with Arthur Dayne because both belong to House Dayne and are elite swordsmen. They are separate characters from different generations. Edric Dayne is another distinct Dayne, a young squire and member of the Brotherhood Without Banners, while Beric Dondarrion belongs to House Dondarrion.