Gwern
Mythical character in Welsh tradition / From Wikipedia, the free encyclopedia
Gwern (meaning "Alder") is a minor figure in Welsh tradition. He is the son of Matholwch, king of Ireland, and Branwen, sister to the king of Britain. He appears in the tale of Branwen, daughter of Llŷr, in which his murder at the hands of his sadistic uncle Efnysien sparks a mutually destructive battle between Britain and Ireland.