That general concept of some "big bad" coming to destroy the world/galaxy/universe has been a big general game plot point for well over a decade now. Across all genres and titles.
Honestly, beside Shinnok who was the bad guy Elder God... they were all useless and a waste of effort, especially Cetrion (storywise at least). If there are Elder Gods i hope they make them actually matter this time.
Fire God Liu Kang is the bad guy and Shang Tsung is the good guy, as Kang is trying to force "peace" on everyone and is in reality a dictator of Stalin proportions. No one in Kang's world is free to be anything but what Kang deems and he uses force to get compliance. So Tsung is a rebel fighting for freedom.... freedom to be good or bad... but freedom of choice.
Superman is the bad guy and Lex Luthor is the good guy, as Superman is trying to force "peace" on everyone and is in reality a dictator of Stalin proportions. No one in Superman's world is free to be anything but what Superman deems and he uses force to get compliance. So Lex Luthor is a rebel fighting for freedom.... freedom to be good or bad... but freedom of choice.