For a story of mine, humanity didn't originate from Earth. Rather, in a planet located in the Alnitam System of Orion's Belt. They then made the "First Empire" by colonizing the rest of the Belt. They then set their sights on the Earth.
At the same time, this First Empire developed a new type of weapons. Unfortunately, these weapons were gaining sentience, so the government of the First Empire demanded their sentinece was to be revoked. Unfortunately, this was too much, so the weapons Turned Against Their Masters, destroying the Empire in the Belt and the only colony in Earth. This also led to the extinction of the Earth's dinosaur population. The weapons were deactivated, but much of human progress was wrecked, forcing humanity to start over within millenia.
edited 10th Sep '17 6:38:18 AM by HallowHawk
So, there's a fictional universe I've been spending a lot of time thinking of how to present in a story, and with the size and scope I'm hoping for it to encompass, I thought it best not to try and be completely original with the various names and concepts, and derive a sizeable portion of them directly from pre-existing ideas. What I had in mind was a world based on Zecharia Sitchin's theories involving the Sumerian gods (Anunnaki) as aliens who originate from the planet Nibiru. I haven't read very much of his material, and mostly know about it from hearsay, although of course, it's a bit too far fetched for me to find believable, and he's most likely a fraud. But I think I can make something out of it (although only from the relevant details; not sure I'd wanna go through everything he ever wrote). I also want to have a syncretic approach to it, so I may decide to incorporate other mythological beings in it.
Basically, what I have in mind is that Earth either becomes too crapsack with overpopulation/pollution/etc or goes full-blown post-apocalyptic, and so through the discovery of a gateway Nibiru, begins to establish new human settlements on the planet, although there already are humans from ages past who got there through magical means. The planet, like Earth, is divided between various nations, mostly populated by Anunnaki, who are much like humans, but with varying degrees of magical ability.
Let me know if there's an effective way of working with the subject matter, or if there's anyone who already had a similar idea for a story.