When the Welsh came in contact with Continental tales that made Lot the father of Gawain, they may have decided Gwyar must have been his mother. Certainly, Gwyar is latterly so presented in Welsh sources. However, as 'Lot' is not really a personal name but a title or designation meaning 'Lothian-ruler', it is not impossible that he was actually called Gwyar.
Later tradition made him the father of Gawain in the Arturian cycle. Gwyar appears to have also been the father of Gwalchmai's sister Dioneta.