This story is a sequel to Iron Hearts: Book 1 - Planetfall

An MLP/Warhammer 40K Crossover, part 2.

Celestia has handed down her order. The Iron Warriors must be defeated and driven from the planet, lest the corrosive grip of Chaos infect their world. With great reluctance, Twilight and Company depart for the Iron Warriors fortress-factory in order to confront the Chaos Warsmith. However, in this mission it is not the might of the enemy that will be their greatest challenge, but their own burgeoning friendships with the admittedly less-than-saintly members of the 38th Company.
At least until the Iron Warriors actually consider them a threat. Then it's totally their military might that will prove to be their greatest challenge.
All the while, the Tau forces lick their wounds and plot their next move. They are far from defeated, and the Iron Warriors have little inkling as to the aliens' true purpose.

MORE EXPLOSIONS!!

(Dark humor warning; minor grimdark)
(Cover art by Nicholas Kay)
(This series now has its own TVtropes page!)
(This series is a contestant in the Tournament of Canterlot, a charity event to raise money for Syrian refugees! Go here for details and donations!)

An MLP/Warhammer 40K Crossover

The Iron Warriors 38th Company has landed in Equestria, entrenching themselves like a barbed hook. They hunt the aliens of the Tau Empire, intent on destruction and pillage.
A small squad is dispatched on a reconnaissance mission, only to find that there is intelligent life on this world besides the feuding space-farers.
Will these improbably adorable and friendly equine aliens turn the damned warriors of Chaos from their blood-soaked path, cleansing them of their dark legacy with the magic of friendship and harmony?

No.
No, that isn't happening.
EXPLOSIONS!!

(Dark humor warning; limited grimdark themes)
(Cover art by Nicholas Kay)
(This series now has its own TVtropes page!)
(This story is a contestant in the Tournament of Canterlot, a charity event to raise money for Syrian refugees! Go here for details and donations!)
(Featured on Equestria Daily 8/20/15 )

Celestia is trapped on Earth.
Not as a human. Not as an alicorn. She's a common horse, an Arabian mare, without her magic, voice, knowledge of the language - not even freedom, forced to work at a riding school.

What can a single Arabian mare do to get back to Equestria from this backwater European country? With only the mind of a princess and a pencil in her teeth, Celestia must find a way home.

[Illustrated] [Alternate Earth] (without Bronies)
Rated Teen for language and some scarce suggestive themes.
Proofreading by AlicornPriest

Polish language version

A brave stallion goes on a quest to save the world by finding a lost princess in an enchanted forest. Things don't work out as he planned.

WARNING: Some spoilers in the comments. Also, a few mild spoilers for the Alicorn Adventure series, though it's not necessary to read those stories to understand this one.

Equestria Daily Page
Goodreads Page
Zabaware/AT&T Natural Voices "reading" by Modoc

Only a few hours after she learned of the Griffon Empire's invasion, Princess Celestia surrendered herself to the griffon army and asked for an audience with the Griffon Emperor.

The Emperor thinks she's here to negotiate Equestria's surrender.

He's wrong.

Spanish Translation
Polish Translation

Equestria has fallen, and life for the ponies and those who they had protected becomes one of hardship as the land loses its magic.

Yet, there are rumors of a vicious pirate, the Purple Mare, and all she is doing to liberate the land. Outside the city of Port-au-Prance that mare, Twilight, waits as a familiar ship approaches...

Inspired by an image by KNA.

*Resubmitted following revisions.*

Luna and Philomena: a hate affair for the ages.

A thousand years ago, Celestia's pet harrier chases a broken Nightmare Moon through the Everfree Forest. A thousand years later, a much-diminished Princess Luna attempts to feed and take care of the elderly phoenix. In neither case does it go particularly well. Set during Season One, slightly before "A Bird in the Hoof."

Now with a Spanish translation by Spaniard Kiwi!

Twilight Sparkle is feeling a little glum about her long-term prospects. Can Rarity help her formulate a less gloomy understanding of the nature of the universe?

This story is a sequel to Together Forever

Princess Celestia relates the tale of how her kind came to be, and the world as it was long ago.

A Together Forever side story.

In a world full of magic, mere words can pose a deadly threat. When simply reading a sign can instantly infect the unwary, and cases start to turn up all around Ponyville, Twilight Sparkle casts the only spell she can find that can give her the time she needs to find the cause of the plague. But then she has to figure out how to stop the epidemic... without being able to read.

Editing provided by Spabble
If you like this, try Rainbow Typhoon
Audiobook on YouTube and for download on SoundCloud
Spanish version translated by MIkimoco
Russian version