Yu is a non-canon character that made his one and only appearance in Mortal Kombat novel.
A demigod described as having the muscular torso of a man, the head of a wolf, the lower body of a mountain cat, the shell of a beetle, the forelegs of a frog, the hind legs of a bear, and the tail of a scorpion. He introduces himself as Yu, the god of waterways and canals.
It was Yu who created Scorpion, because when Sub-Zero killed Yong Park, he disposed of his body in a way that desecrated waterways and canals and wanted to give Yong Park a chance to avenge his death. He instructed Yong Park to find his son Tsui and merge with him, armed him the powers of one of the animals that make him up (the scorpion), and gave him weapons that are the hooks and barbs of those who live on the waterways (the harpoon).