The world of Equestria is very different when you don't have nigh-omnipotent gods and goddesses running about. Without Celestia's guiding light, the Earth Ponies, Pegasi, and Unicorns would probably have never guessed at their gifts. Discord, being the embodiment of Chaos, would work through nature and change, meaning no controlling the weather. Without Luna, the world would be a much darker, scarier place. Oh, and by the way: these aren't your regular little ponies. There will be bipedal ponies with hands, blood and death, and some romance in this story, so if any of those turn you away, well, there's the door.

Not gone? Then...let's begin, shall we?

(Image is courtesy of he4rtofcourage on deviantart. Here, have a link, and tell them how awesome they are. Have fun.)
http://browse.deviantart.com/?qh=&section=&q=Twilight+Sparkle+Mage#/d4fsqot