Prince Valiant's father, King Aguar of Thule (now present day Norway).
Art: Hal Foster and John Cullen Murphy (from installment #2139, October 15, 1978). At this point in Prince Valiant's run, John Cullen Murphy, who had been quietly assisting Hal Foster since 1970, was well into his first decade of drawing the strip over Foster's writing and roughs.
Source: Prince Valiant (Vol. 49): Road to Sorrow's End, comprising pages, or installments, 2168 (August 27, 1978) through 2211 (June 24, 1979). Fantagraphics Books, 2003.