The reign of Morgoth in Arda is over. He has been defeated by the Host of Valinor and the Valar have bound him once more in the chain Angainor and cast him through Doors of Night into the Void. There he has drifted for many long ages, pondering his deeds and his defeats until Ilúvatar comes and offers him a chance at redemption. Softened by ages in the endless Void, Morgoth accepts this chance at freedom. He is given a new body and sent to a new world with the task of learning the values he has shunned for so long. In this new world, under the watchful eyes of Equestria's Valar, the Dark Lord will come to realize that there are yet things greater than the power of darkness.

Also yes, I understand that there's no "e" in Silmarillion, it's a pony pun. Sil-mare-illion. Geddit? GEDDIT?