Sir Brithael is one of Duke Gorlois's most trusted household knights. Sir Bradwen, Sir Gaius, and Sir Monroe met him in Cornwall after their defeat of Saexwulf and he took a liking to Sir Bradwen.
In 488 he was sent to serve as part of the army invading Frankland and was put under the command of Sir Bradwen during the fight. Brithael was very conscious of the insult Prince Madoc gave to him and his Lord when he referred to "traitors to our west."
At the siege of Tintagel, Brithael and Bradwen traded words of camaraderie one last time, but they fought each other in Tintagel when Sir Brithael came to tell Ygraine of the death of Gorlois. When Brithael learned of the cuckoldry of his Lord by Ygraine and Uther he went mad and fled into the night.
Sir Bradwen has been searching for him ever since.