[@Lucidnonsense] I'm not sure it was established that "Earth" was the setting for this RP, but the humans (I believe) are originally from the planet nonetheless. It's the supernatural creatures who are from their own realm.

I guess to give some context, however...In the case of my character, she is a human-born Witch, fathered by the Warlock ruler of the human settlement (The Citadel). The Warlock was once a denizen of the supernatural realm, but he was trapped on the mortal plane (just like the current characters are) like a century ago, and discovered the humans, enslaved them, had them build up a huge stronghold, etc etc. 

But feel free to incorporate your character into the mix however you choose. We are more or less building this world as we go along and it's rather open as of right now.