Welcome. Welcome to the Earthbound Gates. You've come from your home realm, I see. Planning on participating in the war. You're just like all the others. They all came from heaven and hell, wanting to participate in this war. None of them have come back yet. Still fighting. Not as scary as it sounds. Earth's a pretty big place, hard to find the enemy, and even allies, when a whole realm is the battle field. Now, got your confidence back up? Good, because now that your here, there's no going back. Not until your task is done. You enlisted, now you gotta go.
Few rules, now, before you go. First, you have to have a mortal heart. Yeah, that's the biggest catch. Love. Pain. Joy. Sin. Happiness. Guilt. The whole shebang. No, that's not all. You also have to look human. You know, blend. No wings. Gotta keep your powers secret. No matter what. Fighting has to be done under cover. That's if you can find the enemy, who's also blending. I, as the gate keeper, get to watch from up here. Yeah, I seen 'em. Walk right by each other and don't even know it. Demons and Angels being pleasant, or not so pleasant, but not really fighting either. Happens a bunch. Really isn't any way to tell but by spying it out, or by accident. Some of those sensitive ones can tell with a touch. Not many of those, though.
Back to the rules. Yeah, gotta keep up appearances. Don't worry too much, your patron provides you a place to stay. Ways to keep up appearances like jobs and school or whatever. Oh, one last thing. Try not to fall in love with the mortals. Bad things happen. Things out of your control. It won't end well for anyone. I know things happen with mortal hearts... But just try your best, okay?
Well, that covers it. Enjoy the fall.