(Slightly edited from the original version)
Everypony has heard of Princesses Celestia and Luna, the two deity's of Equestria. But there is said to have once been a third deity; a Prince called Dynamo. He was Celestia's old lover, He was the one who completed her. the only pony who Celestia would never out live.
As the centuries went by, Dynamo felt himself dawning into darkness; he was being engulfed in the evil's of Equestria, he could see that it was not the bright paradise it was made out to be, pkus Luna's decent into Nightmare moon didn't help.
He went mad, he transformed himself into another Alicorn of darkness, and tried to take Equestria by force, turning it into a land of darkness, to dwell in the evil it had become. Being the vigilant heroin, Celestia used all her might to cease Dynamo and banish him to the Everfree forest forever.

1000 years later (modern day), Dynamo has returned... with a vengeance. He wishes to rage war against Celesta, and continue were he left off...