Yang Guo traces his lineage to Yang Zaixing, a Song general who participated in the Jin–Song Wars against the Jin Empire. His father, Yang Kang, is the antagonist in "The Legend of the Condor Heroes" and was notorious for committing several atrocities. His mother, Mu Nianci, was Yang Kang's lover. She left Yang Kang after seeing how unrepentant and incorrigible he was, but was already pregnant with Yang Guo at the time.