Nothing suspicious going on here.
Just a group of bugs coming together to create a show for everyone to watch.
...
Twilight doesn't believe it for a second.

It has been nearly sixty years since humanity witnessed the devastation of a World War, or any other kind of large-scale conflict. Equestria's abstinence has been even longer, with battles that rage across the entire land not being seen for centuries. Though both have seen their share of small-scale skirmishes, a duel of total annihilation across a large scale has been avoided by both sides time and again.

But peace is never lasting. For both sides, it lies on a cliff, requiring only one good push to send the participants into a plunge of death. Equestria's unexpected appearance may turn into that final push, as alliances, deception, and distrust threaten to launch a conflict that will lead both worlds to utter ruin.

CREDITS:
This work contains characters and parts created and written by other authors. I am grateful to have become friends with each of them.
Captain Jack R. Williams of the U.S.S. Boxer (LHD-4) created and written by An A10 Warthog
Captain Wilbur Hart and the U.S.S. Tippecanoe (CG-74) created and written by Totallynotabrony
Captain Starry Skies and the R.E.S. Horseshoe Bay (CSG-2) created and written by The Grey Pegasus
H.M.A.S. Sydney created and written by An Iowa Class Battleship
H.M.C.S. Presence created by Sockeye101 and written by The Rainbow Brony
USAF Pararescue team Prancer Two created and written by CptBrony
Carter Jones of the 130th Engineer Brigade written by Routine Blast
1st LT. Silverglow and the Karalian Army created and written by Silverstein.
Sergeant Jeff Thompson of C Troop, Royal Canadian Dragoons created and written by Goldenarbiter
Junior Sergeant Korrector and the 115th Motor-Rifle Division created and written by Kalash93
(More may be added over time)

NOTES:
Rated T for violence and language.
My Little Pony: Friendship is Magic created by Lauren Faust and owned by Hasbro.
Any and all other works belong to their respective creators.

One evening, while in Canterlot to visit her former teacher, Twilight asks Celestia why Princess Luna is rarely ever seen at the castle.

And for the first time, Celestia tells the truth on the matter.

For the record, please know that this was NOT intended as another Celestia bashfic! I like Celestia! This is a story about one version of how I figured she might feel about herself!

Sequels:
Condemnation
Tantabus
The Flower's Grove

While pursuing a splinter of Hive Fleet Behemoth, Captain Sicarius and the Ultramarines 2nd company are caught in a warp storm that carries them and their prey to an unknown planet. Meanwhile, Princess Luna notices something strange in space that could spell danger for all of Equestria. Swept up in a war between the terrifying Tyranid swarm and the vengeful Ultramarines, the ponies must fight for their lives in a war that spans a galaxy.

Thanks to thirdstring_overlord and GiftedMonster for proofreading my newer chapters. thirdstring_overlord also writes an excellent 40k crossover that needs some fans. Go check it out!

Disclaimer: I do not own My Little Pony: Friendship is Magic and Warhammer 40k. They are the properties of their respective owners.

Shadow is a genetically engineered xenomorph who lost everything. His hive was destroyed and he was tricked into going into trap that was to get him off the ship he stowed away on. He crash lands on an unknown world and sees an opportunity to finally live without the worry of WY. When he discovers a small cottage and discovers that there isn't a human living in it but a talking pony, his life flips upside down. These creatures treat him nicer than the humans and he vows to not let WY step foot on this planet. He will start his own hive and hope to find a way to have his species strive once more. Will he succeed or will he be captured and experimented on?

This story takes place between Star Wars Knights Of The Old Republic one and two and after MLP Season 3.
We all know that somehow HK-47 was seriously damaged by the time the Jedi Exile found him. And we all know that he was damaged sometime after the first game. This story shall take place that instead of being destroyed, he was mysteriously transported into equestria.
Do i need to say anything else?
Credit to AwkwardTaco for new title to the story
SPOILER WARNING!
This story will take parts from SW KOTOR that are huge plot twists in the game into the story. So if you are playing the game or don't want spoilers from the first game DO NOT READ THIS FIC! read at your own risk. now on with the story!
Proof-reader: Twi-Guy
Note: finally got around to posting a image for the story XD lazy me

This story is a sequel to Friendship is Grievous

The brutal Clone Wars have at last come to an end. The Separatists are no more, and from the ashes of the Galactic Republic, the Galactic Empire has emerged. Now, the ponies of Equestria must choose their path through a dark and terrible time.

TV Tropes page.

Cover art by Mix-up over at his his deviantart.

This story is a sequel to Princess Celestia: The Changeling Queen

This story is a direct sequel to Princess Celestia: The Changeling Queen. Reading that first is necessary to understand any part of this story.

Co-authored by vren55 and Zervziel

Alternia, sister to Chrysalis, ruled Equestria for a thousand years, disguised as Princess Celestia, while the alicorn slumbered in a healing sleep. Now revealed, Alternia prepares to become Equestria’s first changeling princess, and prove herself to the ponies she loves at the side of her co-rulers Luna and the newly-returned Celestia.

But even as the crown descends onto Alternia’s head, something is stirring in the depths of the Eastern Sea, something that will turn the surface world onto its head. Some power that could destroy Alternia, and all that she loves, before she can even regain the approval of her own ponies.

Will Alternia restore the trust her ponies once placed with her? Will she found a hive? Will she find love?

All that is certain is that Equestria, and the world, will never be the same again.

Now with a TV Tropes page.

Empress Tethys and the Kelpies Created by Zervziel

That Fantastic Cover art is by Plainoasis

Pre-read and edited by:
Blankscape,
FinalFan,
Courage Fire
Cosmic Cowboy

A changeling gets a very risky and clever idea.
Pretending to be an advanced magic doll left as an anonymous gift in front of Twilight Sparkle's home.
It's so audaciously stupid there is no way it's not going to work.

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