Warning: Silliness inbound.

By order of the high lords of Terra themselves, a lone soldier from the Death Korps of Krieg has been sent to the planet Epona to wipe out its Xeno population. Starting with Equestria, the Korpsman has sworn not to leave the planet until he falls or completes his mission.

However, no Korpsman should fight without setting up a proper trench first, and so the Korpsman must dig...and dig...and dig.

Destroying Equestria is going to take a while.

Far, far away from the Equiss system, the queen of blades is readying the launch of her newest weapon. A ship designed to infest an entire planet in secret, readying it for the eventual zerg invasion and softening up even the hardest target, Korhal. Unfortunately for the queen of blades, the untested zerg biotechnology is more difficult to master then she thought and the infestation ship vanishes after launch.

Untold eons later Twilight Sparkle is preparing for her entrance exam for Celestia's school for gifted unicorns only to stop when she sees a star fall into her new treehouse. The young pony sets out in the middle of a storm, intent on seeing this fallen star for herself.

What she finds inside will change not only her destiny but the destiny of all on Equiss prime.

Make sure to check out the sister story to this one.
Trigger warning, parasites. Starcraft Crossover!
Updates twice a month!
The story so far!

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 )

Twilight Sparkle, also known as Medusa, is a hardened criminal mastermind, and the leader of what was formerly the most feared band of criminals in all of Equestria. That was years ago. Now, her crew is in shambles, and she looks to two-bit thug Rainbow Dash to bring it back to its former glory.

With Twilight's genius and experience, combined with some fresh blood, the Mythos Crew may become more formidable than ever.

If there's one thing that King Sombra misses most, it's being inside his old Empire. Sadly, both Shining Armor and Princess Cadence currently rule there in his stead.

Now if only there was a proper way around those two idiots.

Original artwork by Keriwi1: HERE!

For the first time in over a year, Princess Flurry Heart is left alone, creating the perfect opportunity for any ol' villain to come and take her away.

Those poor bastards.

As an agent of the Jedi Council, Revan Vao, distant descendant of Republic Hero Mission Vao, has seen some of the worst examples of sapient behavior that the Republic can offer, when a freak occurrence forces her to crash on Equestria, she is stuck with no way home. Now she just has to adapt to a land based upon Harmony and Friendship and filled with talking ponies.

A HiE-style Star Wars/MLP crossover.

Featured on 07/09/16, thanks everyone!

Final edits and revisions (hopefully) finished on 02/13/17 06/23/17.

Rated Teen for (mostly fictitious) language, innuendo, violence, and Cloud Kicker. Romance tag for later chapters, and Gore tag for a few specific chapters.

This work is a not-for-profit endeavor, no copyright infringement is intended, please don't sue me or any other party that distributes this work.

This story is a sequel to Tantabus, Mk. II

The new and improved Tantabus has behaved itself thus far, but Luna has delayed telling Celestia about it. Until one night when it jumps into Celestia's dreams to say hi and inadvertently reveals itself. Luna must now introduce Celestia to her little bundle of self-aware psychic dream energy sooner than she imagined.

To save her sister and her faithful student, Celestia herself must travel into the ancient tunnels beneath the ruined castle in the Everfree Forest. She, and the guards who accompany her, must face the dark, twisting corridors. Still, what was Luna and Twilight's purpose at the old castle? Why were they unable to return of their own accord?

And what watches Celestia from beyond the light's edge?

Inspired by the heroics of the mysterious mare known as the Stable Dweller, Silver Storm, a guard of the town of Marefort, decides to go on a daring mission to rescue her captured brother. Of course things rarely go as planned and her attempts at heroism drags her into a tangled web of plots and conspiracies as warring factions vie for control over the last great city: Dise.

Spanish Version translated by Spaniard-Kiwi: https://www.deviantart.com/spaniard-kiwi/art/Fallout-Ecuestria-Heroes-996263393