If you could bring in another faction from another game, movie, or comic universe which would you pick? I'd bring in the Covenant from Halo or the Reapers from Mass effect. Grunts running and screaming in the hellmouth would be hilarious. I could imagine reaper forces dropping in for a public event. [spoiler]If you got the #Everyvillainislemons reference you get +1 interwebs.[/spoiler]