Princess Celestia is lonely, she's been that way for a very long time. Her sister was supposed to return safe, and now she's been taken once again. Celestia just wants her sister back. Nopony could have seen the solution would come from the stars.
Aksis. Archon Prime, machine god, and leader of the Devil Splicers. He was the first of the Eliksni to ascend to godhood. But he's stuck indefinitely in a land full of talking, colourful equines.