It is believed that the first Primarch to fall from the Emperor's light was Lorgar of the Word Bearers, who then proceeded to corrupt several of his brothers-including Horus Lupercal himself-leading to the Horus Heresy.
This information was false. Another Primarch had fallen once before and the fall of one Legion led to this Legion's existence and that of one other to be completely expunged from Imperial records.

The Forgotten and The Purged, The Second and The Eleventh, the first two Astartes Legions to face off in an all out war-a war that Equestria was dragged into. Will the Legiones Astartes be willing and/or able to protect this new world as they would their own? Or would Chaos consume this realm through the new crack in reality?

This story is on a 'trail run' sort of thing. I wrote these first two chapters to see how the idea would be received. I may continue if I get to a place in my other story where I feel I can leave it for a bit, or if this is asked for enough - not that I expect it will be Call me a realist.

It began like any other day in Equestria, ponies peacefully living their lives, knowing that if any danger appeared, Princess Twilight Sparkle and her friends would keep them safe, never even entertaining the idea that something was out there that not even the Elements of Harmony could defeat...and yet there was.

As everypony lived their lives in blissful ignorance, fire rained from the stars, destroying cities and burning forests.

By either luck or fate, Ponyville survived, but as the Element Bearers rushed to gather the Elements of Harmony, they found them powerless, for the Tree of Harmony had been destroyed.

When the fire stopped falling, metal pods fell in their place, and from these pods came horrible monsters the size of minotaurs covered in blood red armor, bearing a mark on their shoulders of a black bird and a crimson tear.

The monsters were without mercy or weakness, but as all hope was lost, the Element Bearers heard voices, promising them deliverence in exchange for servitude, caught between annihilation and slavery, Twilight and her friends made a choice...a choice that changed everything.

when evil rules and goodness fails theirs only one hero who can answer the call, and he answers with.

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHH!!!!!!!!!!!!!!!

Hope for unity was burnt to ash in the fires of the Lion's Heresy, yet the Maidens of the Imperium would not yield to the Arch-Betrayer's malice so easily. But hope and determination can only get you so far, For in the Grim Darkness of the far future...There is only War...

Bored and tired of staying in whatever chaotic Warp corner he was in, Leman Russ decides to go visit a random planet and enjoy himself. Too bad alcohol is illegal and a daemon keeps pestering him.

A totally random one-shot made up while out on the road.
I regret nothing.

THERE'S A SEQUEL!
Read Pinkie Pie the Space Wolf now please!

After the Wolf King's infamous visit to Ponyville, Pinkie Pie is sent to help him as he prepares for the final battle.

The God Emperor of Mankind also wants her to join the Space Wolves.

The 42nd Millennium is going to lose its Grimdarkness.

A sequel to Leman Russ Visits Ponyville.

OH SWEET EMPEROR WHY.

Featured on 08/11/14. PRAISE BE TO THE EMPEROR! (I mean Khorne)

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.

A Gellar Field malfunction casts 800 Pre-Heresy Word Bearers into the immaterium just after the Fall of Monarchia.
When they return 10,000 years later, they are forever changed.
Gone are the fanatical worshipers of the Emperor, for in their place stand not the heralds of Chaos, but the Heretics of Harmony.

After a spell goes haywire, Twilight Sparkle and her friends find themselves on a strange planet infested with alien bugs. Lost, annoyed, and just a little sleep deprived, the six ponies seek help in the form of green creatures who love war and hate friendship.

          Upon a distant world, far from the terrors of the grim darkness, resided a peaceful people; ponies, zebras, griffons, hippogriffs, even such fabled creatures as dragons to name a few. Alas that was all about to change one fateful evening in the suburbs of Ponyville.

         Before however we tell this tale, I feel it pertinent to provide fair warning to those who may believe this to be a tale of sunshine and rainbows. Far removed from it, quite the opposite. A grim tale of death, sorrow, despair, and sacrificial heroics lays in wait. Thus, I recommend thou prepare thyselves and saddle up for what shall no doubt be redacted in the history texts by both: our most benevolent ruler Celestia, and the God Emperor of Mankind.