When Twilight first began her experiments in trying to figure out better ways to access the Aether, the realm of magic and souls just outside their physical realm, she did not expect to make significant progress. After all, pony kind has been trying to find out the answer to that line of thinking for centuries.

When she felt herself connect to the other realm Twilight accidentally manipulated its energies in a different sort of way. The Aether bent to her will much easier than before. Getting just a bit too excited, Twilight played with the Aether a tad too freely and the reality-bending powers of the outer realm sucked her into its bottomless depths.

Fortunately Twilight was able to direct herself back to the material realm using the closest, and brightest, soul she could find as an anchor. And the second she looked up at the skull of the skeleton sitting on top of a golden throne, she knew life was about to get more... interesting.

(A crossover with "If the Emperor had a Text-to-Speech Device")

Princess Celestia and Princess Luna are leading together a combined Army of several different equestrian Races against an supposedly terrifying and unfeeling Enemy.

What kind of Threat are our beloved Princesses are really going to face?

A Warhammer 40K/MLP:FIM Crossover.

Special Thanks goes to ARchy4288, Tyrannosaurus_Tux and AlicornPriest for Editing, Proofreading and otherwise helping.
I can only recommend those guys.

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 )

This story is a sequel to Iron Hearts: Book 2 - Ferrous Dominus

An MLP/Warhammer 40K crossover, part 3.

The formal negotiations between Equestria and the Iron Warriors have failed. Yet peace and even cooperation between the harmonious ponies and the corrupted militants blooms in the dark corners of Canterlot and the open streets of Ferrous Dominus. The Elements of Harmony are safe, trade flourishes, and cautious meetings grow into lasting friendships as an unsteady calm descends upon both forces.
Even the Tau threat seems to have mysteriously vanished as the Iron Warriors refuse to assault their hideouts and risk springing the traps of the Fire Caste.
But the Tau have not vanished. The Lamman Sept of the Tau Empire, the Fire Caste's hidden dagger, have come to grips with the slumbering giant looming over their doorstep and have moved forward into the final phases of their plan. Fleets ply the void, hunters stalk the orchards, and in the depths of the badlands a strange device is rapidly assembled for purposes unknown.
The Tau alone know that time is running out, and more than just the fate of Centaur III hangs in the balance.

SIGNIFICANT POSSIBILITY OF EXPLOSIONS.

(Dark humor warning; minor grimdark)
(Cover art by Ahrimatt)
(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!)

This story is a sequel to Iron Hearts: Book 3 - The Sept Lamman

An MLP/Warhammer 40K crossover, part 4.

The Tau threat has passed. The fleet that once thought to sweep aside the tainted pirates of the 38th Company has fled the system. The Lamman Sept is broken, demoralized, leaderless...
... And victorious.

With Lamman's plan put into motion, an alien horde hurtles through the Warp toward the Centaur system, its soldiers without number and thirsting for violence. Equestria's heroes must find a way to stop them, or the entire planet will be overrun with ease and its inhabitants butchered. While they could afford some pretense of neutrality and disinterest in the fight between the Iron Warriors and the Tau, now it is their world that lay in the crosshairs of the foe. Ponykind will need help to survive, and they look to the forces of Chaos for aid. But is there any hope to be found in the darkness?

EXPLOSIONS ARE IMMINENT.

(Dark humor warning; mild grimdark)
(Cover Art by Ahrimatt)
(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!)

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!)

Princess Celestia: Goddess of the Sun, ruler of Equestria, beloved Princess of ponies. She is loved by all, and loves all in return. A calm and wise ruler, she sits on the throne in Canterlot, maintaining peace and harmony throughout the land.

What most don't know is that her past is much darker: She was once a commander of legions, a warrior and scientist of unmatched skill. Thousands of monsters and abominations fell to her forces, slain in the name of an old leader, one entombed within his own throne. Free of her old form, free of the powers of Chaos, she was cast into a new realm, in a new form, with a new lease on life.

She is the God Emperor, Eternal Ruler of Equestria and Lord of the Imperium of Man.

Has a TvTropes Page. Please contribute.

Comments contain spoilers. YOU HAVE BEEN WARNED!!!

This story is a sequel to The God Empress of Ponykind

A message rings through the Warp: "The Game is broken, only Destruction remains". Celestia hears it, fearing for the lives of her former subjects and those of her beloved ponies. Unwilling to sit idle, she has chosen a dangerous path: return to the Imperium, take up the mantle of Emperor of Mankind, defeat the coming storm, and save Mankind once and for all.

With Twilight Sparkle to aid her, Celestia faces new challenges and new enemies. Her forces are scattered, her people assaulted, and the enemies of Man grow stronger with each passing day.

The Time of Heroes is gone. Now comes the Time of Ending.

Sequel to God Empress of Ponykind. Reading that first is strongly recommended.
Rated T for 40K related violence, but that might change at some point.
Comments contain spoilers. You have been warned.

Accessing Files... Accessing...
File Found.

Name: Anton Ilario
Troop Number: #35863756-878
Location of Birth: Elysia Secundus, Elysia Prime
Date of Birth: 2.456.922.M41
Unit: 158th Elysian Drop Troopers
Rank: Trooper (Field Chirurgeon)
Previous Campaign: N/A
Current Campaign: Second Offensive against House Lysimicus forces on Veyland Sinestre.
Status: MIA (Believed KIA)

Leaving File...
Imperial Thought of the Day: Suffer Not the Alien to Live.

This story is a sequel to From Dust

Twilight Sparkle is many things, but above all else, she is a friend. Her most recent acquaintance is, however, a most unusual sort.

Never before has Equestria played host to a traitor space marine of the Adeptus Astartes.

As an armor-bound soul with a body burned to naught but ash and dust, how will this former being of war fit into the love and harmony of the pony domains?

Surprisingly well, all things considered.

A Warhammer 40,000 crossover.