He sprinted through the corridors of the Mechanicus base. The straps on his shoulder rubbed his flesh raw through his form fitting synskin suit. Behind him, an explosion rocked the base. Rockcrete dust and smoke filled the air and obscured his vision. It didn't matter as much. The generator room was close now.

Four forms jumped at him through the smoke. The Chaos corrupted forms of Skitarii shot at him with tainted arc rifles. He dodged the deadly arcing lightning with a roll. It struck the walls near him, scattering across the ferrocrete walls. He aimed and fired three times, destroying servos and flesh alike. Rifle clicking empty, he swung the Rifle across his shoulder and rushed the final Skitarii with all his strength. It's mechanical horror of a face drew into a confused expression before he punched it. The Ring smashed into metal, but he felt something break in his hand. The Skitarii fell hard.

Another explosion rocked everything and sent chunks falling from the rood. He recovered and kept running. He ran into the generator room and slammed the button that closed the door. Strange crescents filled the room, hooked up to screens that displayed statistics, he neither understood nor cared about. He recognized them instantly as Necron Pylons. It was strange but not confusing. It was unsurprising that the traitorous Mechanicus stationed here would experiment with Xenos technology. He recognized his primary objective, of the more natural fusion reactors of Imperial design. Walking across a metal walkway, he unpacked the charges and set them in key locations within the core.

Satisfied, he ran to the sole exit he came in through.

The door exploded into ferrocrete chunks as dangerous as any Basilisk shrapnel. A piece exploded across his torso, tearing his suit and stumbling him. He dropped with an agonized roll and took cover behind a pylon as the Skittari Alpha entered the room. He was the height of two normal men, more machine than flesh, with extra limbs. Two held a smoking galvanic rifle. Others held blasphemed radium weapons. They pointed at the pylon the Assassin was hidden behind.

He jumped just as the pylon exploded into sparks. It began glowing with power. The Assassin felt something electrical permeate the air. He ignored it and calculated his next play. The Alpha was fast but he was faster. There was a weak point near the neck, where the augmentix limbs connected to the torso.

He fired as he jumped, calculating trajectories in terran microseconds. They should've been clean hits. Instead, they exploded across an invisible barrier. Force shield. There was no way he could destabilize it with his pistol. He would need to use the Rifle. He twisted, smashed into a metal bar, and landed wrong. His ankle twisted, sending him stumbling towards the Alpha.

A massive armoured limb smashed into his face, sending him tumbling through the air. He landed on his tailbone, skidding to a stop beside the broken remains of the door The rifle detached from his back and landed a body length away out of reach. Every part of his body hurt, and he could taste blood in his mouth.

The Assassin raised the pistol and fired again and again. Each round exploded uselessly against the shield. The damaged Necron pylon filled the air with an unnatural neon-green glow as the Alpha walked past it. It stopped and stared at the Assassin with what looked like a snarl. He realized it was a smile.

It stopped and raised its weapons. The Necron pylon began whining. There was one more round in the Exitus pistol. He realized he would not survive. He adjusted his aim past the Alpha, towards the charges he placed.

"For the Emperor…"

The Alpha turned. He fired. And then the room was filled with light.

_︻┻┳══━一_

He woke up with a splitting headache and blood in his mouth. Even so, he tried to get up, gasped as a sudden wave of pain racked his body. Collapsing onto the hard ground, the jagged edge of a broken rib stabbed into his lung, as a dozen other wounds demanded attention. He closed his eyes and took a few deep breaths. He accepted the pain, welcomed it like an old friend. It told him he was alive.

It wasn't the only evidence to that point. If he had died and his soul had entered the Warp, it would've been torn apart by its denizens and consumed. It was the first thing the Lord Assassin had taught him after he arrived on Terra. He frowned at this knowledge.

There was no way he had survived the blast. The satchel charges he had set off would've destabilized the fusion reactors on the mechanicus base and vaporized everything in a kilometre wide circle. He was three metres away from the epicenter. Still, somehow, he was alive. He opened his eyes and saw black. Had he gone blind? He panicked for a moment before calming himself down.

The spy-mask must have been unpowered. He saw none of the familiar overlay and felt no continuous relay of information. He shivered, not only from cold. The spy-mask was an essential component of his arsenal, master-crafted with scanners and auspex that allowed him to monitor enemy communication channels and his own surroundings. If it was broken…

He tested his right arm. It protested with pops but moved to the side of his face. He restarted the mask as he gave a quick prayer to the Omnissiah. He held his breath as a tense second passed. Then two. A faint clicking and whirling started. He allowed a faint sense of relief to rush through him.

Another moment passed before he heard a faint beeping, followed by the electrical hum of his spy-mask powering on. Sensing his consciousness, it reawakened from its power saving dormancy. He shivered as it reintegrated with him, scanning his body through his own nerves. A moment passed as it processed the information, before it began blasting his mind with status reports and statistics. He absorbed it all with ease, if not comfort.

He had three cracked ribs, one broken, a sprained ankle, multiple second degree burns, concussion, and a dislocated left pointer finger. The mask diagnosed his injuries and administered a stim. The stabbing pains subsided somewhat, replaced by the itch of muscles and skin knitting back together. Satisfied inwards, the mask looked out.

The atmosphere was breathable, with an oxygen level higher than most planets in the Imperium. Strangely free of pollutants. The gravity was 0.9Gs, as compared to Terra. The temperature was cold, three degrees below freezing, but survivable, even in his current injured condition.

His confusion mounted. It was unlikely he was anywhere on Aricia. The planet's climate had been destroyed by eons of manufacturing, raising the temperature to a scorching heat. There was no more natural cold. All of it was manufactured, designed to keep workers alive and producing. Even the extreme poles were barely cold enough to shelter liquid water from the malignant gaze of the binary stars the planet orbited.

So where was he?

He tested his body. It felt better than when he first awakened. He pushed himself to a sitting position, his Ring poking into the ground.

Evergreen trees filled his vision. A cold breeze chilled his skin through the tears in his synskin suit. The sun was bright but brought no warmth. Curiously, there was no sound of wildlife despite the vegetation. No birds chirped, no insects buzzed. His Rifle lay next to him, and he picked it up and lay it on his lap.

The Exitus rifle straddled the line between a sniper rifle and an artillery piece. Unloaded, it was fifteen kilograms. He checked for obstructions while reaching for a magazine on his body. Satisfied, he rammed the magazine home. The Rifle worked its charging handle automatically.

It was closer to twenty pounds now, ten rounds of 25mm adamantium-tipped turbo-penetrator rounds loaded. Each was hand-crafted by master craftsman in the Officio Assassinorum and could crack the faceplate of a heretic Dreadnought. The sleek machine spirit inside hummed, eager to begin. The weight and feeling reassured him as he slung it across his back in a practiced motion. He drew the pistol and did the same.

He took a deep breath as he stood up. The blood rushed to his head and made him feel dizzy. For a moment, he almost passed out. The sensation passed and he began a sit-rep.

He was injured, but not fatally. The stim had taken the edge off, but he would need to check his wounds as soon as he was able. Most of his equipment was functioning. The synskin was damaged, but still provided a twenty five percent boost to his power. The suit would repair themselves in time. The spy-mask had a broken eyepiece and about two days worth of power left. He could charge it if he could find any sort of electrical output. In the meantime, he would keep it on its power saving mode. He set it on scanning for communications and possible nearby settlements, human and otherwise. Better Xenos than empty. He could find a way off-planet with Xenos. Each agent was trained in espionage, and how to operate the heretical technology of both the Eldar and the Necron. Granted, he was Vindicare, and not as skilled at either than Callidus at trickery, but he could make do.

Something large rustled in the bush next to him. He turned around, staring. The sound stopped.

He had about two mags of standard Turbo-Penetrator ammunition. One Hellfire magazine for biological threats, and one Shell Breaker for shielded. He could make more if he found the materials, and some sort of workstation. For the pistol, he only had two more Turbo-Penetrator magazines. A common assumption was that the Exitus pistol shared ammo with the Rifle. While Rifle cartridges could be converted to pistol ones, it did not work vice versa. And if he ran out, he had his knife. And the Ring, of course.

Another rustle broke his concentration. It stopped again when he looked at it. This time however, he turned on the thermal overlay. Two forms stared at him through the underbrush. He felt the hair on his neck rise. Pivoting, he scanned all around him. One was behind him and three more covered his flanks. Six in total.

Surrounded.

He readied his pistol and drew the knife. The forms got closer and closer.

A black beast with a white and red bone mask broke through the underbrush. Its eyes were red and filled with hatred. Around him, similar forms came at him. They reminded him of the Fenrisian wolves found on the home planet of the Space Wolves. If they had the same behaviorisms, he had to stand his ground.

The one behind him charged with a savage roar. He sidestepped its initial attack and brought the knife down, smashing through bone and flesh. It fell, spinal cord cut. The rest stared at their fallen comrade before coming at him at the same time.

He shot three of them as they charged, adamantium jacket punching through fur and bone with ease. His knife glistened as it slashed through the air, slicing the jugular of one more.

The final slammed into his back, trying to bite his arm through the synskin suit. He punched, putting muscle and augmentix into the blow. The wolf fell back, bones shattering. He grabbed it by the scruff of its neck holding it out an arms length away. It jerked violently, trying to bite him. After a moment's study, he broke the thing's neck.

The corpses of the fallen were already dissipating leaving a bad taste in the Assassin's mouth. He had originally thought them to be merely a violent sub-sapient predator. Now, it reeked of the taint of Chaos. Every other target, even the foul races of Xenos, were predictable in their goals if nothing else. Only the ruinous powers served no purpose but to destroy and consume. If the powers of Chaos could manifest themselves in a physical form on this planet…

It had to be destroyed immediately.

The spy-mask beeped once. A signal had been discovered thirteen clicks north from his position. The encryption had been rudimentary. Looking around, the thermal scan detected no other forms. If nothing else, he needed information. The mask displayed the symbols of the native language. It was completely undecipherable with no discernible letters or spacing. He thought about it for a second. Either that meant that the local denizens were Xenos or that they had been isolated from the Imperium so long, that they no longer spoke standardized Low or High Gothic. Neither was a hopeful option. Xenos were untrustworthy and violent by default while a world separated from the Imperium could be heretical. He looked at the intercepted message again. While the spy-mask could do many things, translation without a key was not one of them. The only source of information was through its inhabitants. He tentatively stretched one leg. Then the other.

And began walking.

_︻┻┳══━一_

Author's note:

This is my first fanfiction combining my two favorite universes, RWBY and Warhammer 40k. The main character is an OC, a Vindicare assassin far from home and reinforcements. I'll flesh out his story eventually. RWBY characters should show up next chapter. If you like this story, please rate and comment on how to improve. Thanks!