Counterpart of Gawain in Welsh legends.
He was the son of Gwyar, the brother of Gwalhafed, and the nephew of Arthur. One of Arthurís best warriors, he is described as noble, brave, and courteous. His character bears a relation to the Irish hero Cu Chulainn.
The root of his name, Gwalch, means 'hawk', and mei may indicate 'May', as in 'Hawk of May'. As his epithet 'fab Gwyar' indicates, he is the son of Gwyar. Gwalchmai implies a hero in war.
He was Arthurís best rider, and accompanied Culhwch and other warriors in Arthurís service on Culhwchís quest to find Olwen. His companions were Cei (Kay), Bedwyr (Bedivere), Cynddylig the Guide, Gwrhyr the Interpreter and Menw fab Teirgwaedd. Gwalchmai fab Gwyar later resurfaced in the Arthurian cycle as the knight Gawain.
He also accompanied the search for Owain when he was missing. Gwalchmei was one of the knights that Peredur saw as a youth, prompting Peredur to become a knight himself. Gwalchmei owned a magnificent brocade given to him by the Earl of Anjouís daughter. A Welsh Tristan fragment calls to him "Gwalchmei Golden-Tongue", referring to his negotiating skills. He is said to be one of Arthur's Three Golden-Tongued Knights of the Island of Britain.
A Welsh stanza places his grave at Peryddon.