Shang Ti is a non-canon character that made his one and only appearance in Mortal Kombat novel.
Five thousand years ago, the wealthy and grateful Yellow Emperor of the Flowery Kingdom erected the first temple to a god. He did not feel worthy enough to honor T'ien himself, so he chose to build a shrine in honor of Shang Ti, God of the Mountains and the Rivers.
Little else is known about Shang Ti as he is never mentioned again in novel.