WarMetal Tyrant Storyline?

I've recently begun playing this game, and I'm curious as to what the storyline is actually about.

Is there actually a backstory? Some players tell me it's based off of some other game or something, and I'm not sure exactly what exactly happens.

Simply put, why are all the factions there? Why do the Imperial exist where they are, what planet are they on, etc.

If you can, post your answers in a spoilers tag. Thanks!