MLP/Undertale crossover.
Not a PWNY-verse story.

Long ago, the Monsters and Humans fought a great war. The Monsters lost, and were sealed in the Underground. It would take the power of seven human souls to break the barrier that kept them imprisoned. They only had six. And so the Monsters waited and hoped, praying that another human would find their way to the Underground. Some thought the seventh soul would give their King the strength to break the barrier. Some dreamed of a human who would be their friend, and save them all...or had nightmares of one who would bring back the war.

...but nobody came.

...but somepony did.

Eons after the war, with no way to tell how much time had passed above, a tiny blue filly with wings and horn fell into the underground, calling for her Mama. None knew the poor creature's nature or origins...but her soul was powerful with magic, even more so than a human soul.

None can know what will come...of this little 'Woona'.

Cover art by Sanyo21

Long ago, two races ruled over Earth: MONSTERS and PONIES
One day, war broke out between the two races.
After a long battle, the ponies were victorious.
They sealed the monsters underground with a magic spell.
Many years later...
Legends say that those who climb the mountain never return.

This is an Undertale X MLP:FiM mash-up, but it will still have potential spoilers to the game. If you haven't played it yet, then turn away now. Also, in keeping with the game, the main character is you, the reader.