Brastias originally was a knight of Duke Gorlois.
Merlin diguised Sir Ulfius as Sir Brastias on the night Uther begat Arthur. Later, on his accession to the throne, Arthur made Brastias
warden to wait upon the north from Trent forwards, for it was that time the most party the king's enemies.
Brastias served Arthur well in the first wave of rebellion. With Ulfius, Brastias traveled across the Channel to summon Kings Ban of Benwick and Bors to Arthur’s aid. On the way, the two of them had to joust down eight of King Claudas’ knights who tried to stop them.
Brastias fought in the battle of Bedegraine, but afterward seems to drop out of Malory’s account, with no mention that he remained with Arthur long enough to serve at the Round Table. Brastias must already have been at least approaching middle age by the time of Arthur’s coronation, and he may have retired early into a hermitage.
He had originally been in the service of the Duke of Tintagel (possibly Gorlois).
He probably is to be identified with the hermit Brasias of Malory’s Book XVIII.