Master Yo is the Grandson of Po.
They're both Martial Artist Pandas, with only one letter difference in their names. Also, Ti and Chai, who were Tigers, were Master Yo's parents (it's the same universe where a dragon can breed insects), so it could be presumed that eventually, Po hooked up with Tigress, gave birth to either of them, and that Yo descended from them, making Yin and Yang their great grandchildren. The Nightmaster's magic is dark form of Woo Foo.
