Incarnate

-Begin-
Forest landings were hardly the forte of Valkyrie pilots, but after the messy jungle conflicts with the Orks of Kaurava II, the men of the 45th Styx regiment had somewhat adjusted to the unpleasant feeling that they could, at any minute, crash and be impaled upon an entire forest of razor-sharp branches. Regardless, Dane had chosen a forest at nightfall, as it was the only stealthy approach into what appeared to be a nearby settlement, the only question then, was where to go first. The minute the many Valkyries had left the LZ, all light seemed to drain from the area, enveloping the fifty guardsmen, chimera, and ever-so-slightly insane priest leader, in absolute darkness. And thus, they were lost.
"Men," the priest said finally, "beyond these woods, may lie two things." By this point, the fifty guardsmen, and the entire chimera crew were kneeling before their bold leader. "Either the foul dregs of Chaos, or pathetic, heretical Xenos." At the mention of either option, the men seemingly grew more restless, beginning to claw at their weapons in primal anticipation.
"On this night! You shall bring great glory to the Imperium, the regiment, and yourselves. We shall return home, either soaked in the blood of traitors," At this, the men cheered, "or bearing the skulls of this decadent race of alien cowards!" More savage cheering, almost to the point of it becoming tribal. "They have languished in the shadows for far too long! Insulting our Emperor, with each breath they take, using foul magics, and granting the chaotic hordes asylum though their blistering incompetence and cowardice!"
A short ways away, a pony guardsman, sole survivor of the river clash, had made his way ashore, and into Ponyville. Being the scared conscript that he was, and lacking what little honor his squad had had, he could only thing of one thing to say...

"HEEEEEEELLLLLLPPPPPP MMMMMMMMMEEEEEEEEEE!"

Back again in the forest, the ears of every guardsman present detected the shriek, and responded with confusion. That is, until the priest started up again. "You see soldiers?! They already fear us! Now, let us bring the wrath of the Emperor down upon these savage Xeno scum! FORWARD!" The Chimera came online, and it's plow easily decimated the trees in its way, followed up by fifty guardsmen, ready to spill blood.

"How is he Flutters?" Applejack asked Fluttershy, the two having just relocated the conscript pony to the town center.
"He-he'll-l be okay, but the stuff he said, could it r-really be true? A poor animal, taught to kill? All those guards? And the metal men? Who are they? And why? WhycomeandstartallofthiskillingLikeabunchifevilbulliesitsjudtnotniceorfairor-" Applejack quickly shoved an apple into her friend's mouth. "Fluttershy, I think it's just the poor colt's nerves is all, like when Big Mac learnt' where fillies come from? Jus' about lost himself! Remember?" Fluttershy remembered, and laughed for the sake of her friend, but still worried horrendously.
"Maybe it is just his nerves, who knows?" She said with false security in her voice. "After all, whose ever heard of 'metal barbarians' why, I've ne-" "I have" Fluttershy yelped in surprise, as the form of a familiar human made itself known. "Alexander? You've heard of the metal men?" Shy asked, curious as to why Alexander looked so worried. "They're called 'Chaos Space Marines' and they're evil incarnate" he said dramatically. "Chaos? Like Discord's chaos?" Applejack asked Alexander with a smug look of nostalgic bravery on her face, still prideful from their original victory over him. "Unless Discord guts you alive, fastens your head to his belt as a trophy, and sacrifices your soul to his dark Gods, not in the least." Fluttershy looked sick, and Applejack seemed to be in shock. "Can the elements stop them?" Fluttershy asked with a shred of hope in her voice. "I've seen entire regiments of good men, laid to waste by just a handful of... them. So, most likely no." Fluttershy and Applejack were now entirely shivering, terrified of the reality they were now going to face, when they suddenly heard a loud rumbling coming from the formerly dark road which lead to the Everfree Forest. "Wha-what's that noise?" Shy asked with full-fledged fear in her voice.
They got their answer in the form of a deep-green rolling machine, which seemed to appear in an instant, and sit before them in abject stillness. It shined a bright spotlight on the three friends, which kept them from immediately seeing that fifty silhouettes had joined the rumbling... thing.
"Are you the guardsman Alexander?!" An aged, but incredibly loud voice asked from somewhere. Alexander drew his lasgun, and quickly took position before the two ponies, only to realize that the commotion had drawn most if the ponies inside the town center outside. "Who's asking?" Alexander replied in a smug, fearless tone.
"Why in the name of the Emperor are you not killing these Xenos?" The voice asked. "They're my friends sir, and if you mean them any harm, I swear I'll-"

"Kill the treasonous wretch"