A kind demon...it seemed too strange to be true, didn't it? Alastor's good nature had become widely known...but his own innate darkness, particularly with his full power at his disposal, had made him an easy target for the Nightmare Forces.

It had started with dark clouds spreading out from his castle above the Night Market, blanketing the skies as far as anypony could see. The sun was blotted out, casting the world in a dreary gray occasionally lit with violet lightning.

Then Nightmare Storm had made his entrance in the sky, flanked by no less than a hundred of his bloodgoyles. Somehow, his voice carried all throughout Ponyville, deep and warped.

"Bow, you mortals. Your new emperor has finally decided to take his rightful place. The weak among you shall give your hearts and swear eternal loyalty, while the strong might rule beneath me...if you acknowledge me as your master. Your days of peace and sunshine are over...now it's my turn to see the world I want!"

And then the music started.

"Vision born of dream-like lucid flames
Violet light mastered by faceless names
Thundering passion or a timeless force
Voices speak of demons rising forth

Once were dreaming
Now are living
Feel the rain begin to pour
Hear the wind lift off and soar

Eternal storm
Restless souls
Eternal storm
Restless souls embrace the dying dawn

Nightmares destroying mortality
Creating dreamscape reality
Lost and forgotten our spirit sought
Forced upon us ways of lifeless thought"

...Yeah, somepony might want to stop him before he turns Equestria into a kingdom of lightning and bloodshed.