Gwyer Warhein was the half-breed captain of the Green Riders some two hundred years ago. He betrayed the last Sealender king to help deliver Smidhe Hillander to the throne. He bears the same brooch that Laren uses that tells them if what someone is saying is either true or false. When Captain Mapstone collapses with the advent of wild magic in First Rider's Call, the ghost of Warhein contacts Laren to help her control her ability.
Warhein is described as having long gleaming black hair, dark-skinned, with ritual tattooing across his cheeks that marks the passage of a boy into manhood in the Under Kingdoms. Some notable achievements of his time are helping Smidhe to the throne and changing the chain of command for the Riders, making them report only to Captain and King instead of the Light Horse, making it easier to use Riders' abilities undetected.