Grace is over, this can be added now
End of story
The Dawnbreaker's ring glowed brightly before shutting down, along with everything else around him. All light disappeared, leaving only horrific constructs that destroy all. Crunching and snapping and screams of the princess of the night disappeared into the void of space. Little by little, light returned and all that was left of the princess was a mangled corpse. But something was wrong and the fallen lantern stood in place, unmoving. A few minutes later, a portal opened up and out came the creature that started it all, a smiling figure, the Batman who Laughs.
"I assume you had a great time at the land of magic horses. Make them fear the dark once more, huh?" asked the smiling one before noticing the carcass "Would you look at that, you killed their ruler! She doesn't appear so majestic when the lights are out".
The Batman who Laughs began poking at the carcass and in an instant, the Dawnbreaker's ring glowed.
"Do not touch the queen..." said the fallen lantern, an odd glow surrounding him.
"Bruce? I never thought of you as a sim..." said the smiling one before being silenced.
Meanwhile back on earth, Twilight and Celestia looked around anxiously, waiting for the prophecy to fulfill itself. And yet even at the dead of night, Nightmare Moon did not arrive. The princess of the sun was not relieved by this revelation, fearing for her sister's life and worse, that something far more powerful has replaced her. She quickly teleported into the moon and that's when he saw, The Dawnbreaker, now dressed in dark blue clothes with green streaks, a symbol of the moon overlapping his lantern symbol.
"You must be the other ruler! As you can see, something went very wrong..." said the Batman who Laughs, now nailed to the ground with darkness closing on everything.
"Kill the sun. Activate blackout" said the Dawnbreaker, the darkness befalling everything around him as he chanted the poem Nightmare Moon so desperately wanted.
With darkness black, the sun shall fall
The darkest days will come for all
I'll vanquish light down to its core
And Nightmare Moon shall rule once more
Also I know the whole thing is supposed to rhyme but this poem grew on me when I wrote it the first time and besides, Dawnbreaker's working with what he's got