Humans.

Truth or myth? Ancient lost civilization or just an old pony's tale?

No pony has ever seen one, and most haven't even heard of them. But Lyra knows that these wonderful creatures are more than just old legends, and she's going to find out... and possibly drive her roommate insane in the process.

Once upon a time, in the magical land of Equestria...

One week ago, Twilight Sparkle was crowned the fourth Princess of Equestria. Tonight, Ponyville hosts the 1003rd Summer Sun Celebration, and Princess Celestia and Princess Luna want a vacation. With two fine young princesses like Cadance and Twilight to take over for them, nothing could possibly go wrong.

(Title image hacked together from vectors by sakatagintoki117 and Chrome-MMVII.)

The local crime syndicate sees Miller's lack of ID as an advantage. Before too long, our poor former human is eyeball-deep in the scum of Canterlot. Forget going home - the challenge is trying to stay one step ahead of police, criminals, and a pair of persistent mares.

In 2185, during his campaign against the Collectors, Commander Shepard discovered a previously unknown species whose origins predated any other race in the modern galaxy. Following a daring rescue from their ancient sanctuary, the Equestrian Herd was brought back into the galaxy where, for the first time in eons, they must walk their own path.

Knowing full well the terrible threat that lingers on the edge of the galaxy, the leader of this newly freed race fights to secure her people’s future while attempting to prepare for the storm on the horizon.

This is her story.
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The long awaited Sequel to Mass Effect 2: The Equestrian Equation This is a reader directed story. Your choices will shape events.
If you favorite, also like! It's one little button click that makes all the difference.

Also, this series has its own TVTropes page now! (Special thanks to user CrowMagnon for setting it up).

This story is a sequel to Hard Reset

After the events of Hard Reset Twilight's life and mental well being are slowly returning to normal. Her recovery is cut short, though, when a letter arrives informing her that the time loop spell she cast is causing severe damage to space and time itself. In over her head, Twilight tries to summon anypony who will know how to fix it. The pony she gets is the last one she ever thought she would meet... and nothing like she expected him to be.

Available in Spanish thanks to dgs1993
Series TV Tropes page

Derpy Hooves is secretly a changeling.

Nopony particularly notices, or cares.

(New 9/15/19: Spanish translation by Spaniard Kiwi! Thank you!)

Princess Celestia always knew that Twilight Sparkle was destined for great things, but she never revealed the source of that knowledge, not even to those closest to her. When the day of Twilight's true destiny finally arrives, can Celestia fulfill an ancient promise to save Equestia's past, present, and future, even it means saying goodbye to Twilight forever? How can Celestia refuse her mother's last wish?

Art by the inimitable Harwick

Twilight isn't having a very good day. An experimental spell blew up in her face, an army of changelings is attacking Canterlot, and she just died. Yet somehow, it looks like it's going to keep going downhill from here.

Given the chance to correct what's gone wrong, Twilight swears she's going to fix all this even if it kills her. Which it will. Frequently.

Cover art by Pixel Prism
Spanish Translation
Series TV Tropes page

While Princess Luna is away celebrating Nightmare Night in Ponyville, Celestia tries on a strange black bauble from her sister's jewelry box. The result will be the creation of the most terrifying thing Equestria has ever seen. The Sun herself turns against all the ponies in Canterlot. Can Luna and her Lunar Stallions possibly hope to stop her? And if so, does Luna have the fortitude to strike down her sister in the end?

FEATURED May 16th 2012!

Brought to you by Loyal2Luna, this new Downloadable Content for Mass Effect 2 brings the fight to Equestria.

Just about ready to embark on their mission to stop the Collectors from further abducting human colonies, Commander Shepard and the crew of the Normandy SR-2 are given a new priority, when the Illusive Man tasks them with investigating the mysterious disappearance of a Cerberus science team.

Soon, what begins as a simple search-and-rescue unveils a mystery millions of years in the making, and the Commander finds himself thrust into a situation he couldn't possibly have prepared himself for.

Join the Hero of the Citadel as he uncovers the secrets, combats the demons, and ultimately decides the fate of the impossible world known as "Equestria."