A/N: Well uh…. Hey everyone. This is a bit different that what I am used to so please leave a review to let me know what you think of my smutty little fic here. Obviously, don't read if you are under 18!

Disclaimer: I do not own either Warhammer 40K or Mass Effect. And it contains sex.

Lieutenant John Shepard of the Ultramarines stalked through the desolate hive city ruins. He had been one of a hundred Adeptus Astartes deployed to this planet to cleanse it of the demonic taint present. Now he didn't know if he was still one of a hundred or the last of a hundred. His drop pod had veered off course during its descent and had landed right in the supposed headquarters of the chaos cult. However, ever since leaving his drop pod his auspex had not picked up anyone or anything else in his vicinity.

Still, despite what his armor's systems told him, Shepard had the distinct feeling that he was being watched.

A piece of debris fell from the broken window of a nearby window. Shepard jerked his bolt gun up and fired a few shots into the building. The exploding shells reduced that specific section of the wall to rubble. Through the cloud of dust, Shepard could see…

Nothing.

There was nothing.

Someone-something here was toying with him.

"Well hello there." A velvety feminine voice said from off to his left. Shepard turned to train his sights on its source.

In front of his was what he quickly realized to be the greater daemon of Slaanesh that headed the local chaos cult. They had been briefed on possible ways of banishing it along with the daemon's name.

Tali'Zorah.

The daemon's form was as tall as his own, albeit much curvier. Her large breasts strained against the confines of her top, while her toned stomach was left completely bare for all to see. Long jet-black hair framed her elfin face, which was lit by the light of her silver eyes. But undoubtedly, the most alluring part of the daemon so far was her hips. Adorned with a long, thin loin cloth that only served to cover her womanhood, leaving her bowed back legs completely bare, the daemon's hips were larger than his own even while in his primaris armor.

Shepard shook himself out of the trance the daemon had put on him and raised his bolt gun in warning. "Stay back daemon! I am clad in the holy armor of the Emperor! And in his name, I will banish you back to whatever chaos hellhole you crawled out of."

A pout crossed Tali's face as she began to saunter closer to him. Her plush hips swayed with each step in a constant, consistent, hypnotic motion. She crossed her arms behind her back and leaned forward a bit, giving the space marine a perfect view of the cavern of cleavage that her bra was struggling to contain. "And why would you want to do that? Aren't you tired of all the fighting? Don't you want to do something else that starts with the letter f ?"

The daemon's eyebrows rose in a suggestive manner, and a rather goofy grin crossed her face. She was no doubt praising herself for her groundbreaking flirting. The space marine rolled his eyes. "Really, that's the best you could come up with?"

Tali scowled at him. "C'mon, it's not like I've done this before."

"Do you wanna try again?"

The greater daemon seemed to mull over the space marine's offer before finally nodding. "Yeah, sure."

Suddenly, Tali was in front of him, moving faster than the average human would have been capable of comprehending. She shoved her large, shapely thigh between Shepard's legs and right up to his crotch. However, instead of crushing the fragile organ, she instead simply smushed her leg up against it, pushing his crotch guard up against his already hard dick. It was rather uncomfortable to be honest, but in some perverse way that only made it better.

"How's that for better?" Tali asked, a much more seductive grin playing across her lips.

"Mu-much bett-HERETICAL!" The space marine snapped himself out of his trance and gently shoved the daemon away from him.

Despite the lack of force in his blow, he sent her sprawling across a piece of nearby rubble that looked suspiciously like a very large bed. She landed on her hands and knees, facing away from him….

BY THE EMPEROR HER ASS WAS MASSIVE

Not only was it big, but it was perfectly shaped as well. It was as if it had been made by the Prince of Pleasure himself for Tali's figure. It flared out to the side with her hips and curved back out towards him, forming a solid shelf of skin and muscle. Her booty wobbled slightly as the daemon balanced herself, showing that while toned, her backside also had enough fat to give it the right amount of jiggle that would drive even the master of mankind crazy with lust.

Shepard restrained himself from reaching to stroke his cock. After all, it wouldn't be fitting to ruin the fun too quickly.

"OH SPACE MARINE! I AM DEFEATED !" Tali let out an ear-piercing moan of agony at her mortal wound. She shoved her sizeable butt into the air as she arched her back into a downward dog position. "I am powerless to resist you!"

The daemon bit her lip in anticipation as she heard the valiant defender of mankind behind her begin to unbuckle his suit of armor. She let out a shaky breath as she heard his heavy footsteps as he stalked towards her. And she let out a scream of ecstasy so intense that it clogged her throat with pleasure and came out as a soft squeak.

Goosebumps crawled up her arms as the cool ceramite of Shepard's armor pressed against her bare ass. Instead of thrusting in and out as he usually did, Shepard pushed his cock as far as he could manage into her vagina. After a second of relishing in the pressure that her warp-spawned body provided to his genes-seeded manhood, he pulled out. Confused, Tali looked over her shoulder to see what her human was doing.

He was currently struggling to pull down his pants with an eight-inch long raging erection in the way.

"Here, let me help." She said before turning around and assisting the warrior with de-armoring himself. When they finally managed to pull the last piece of cermaite plating off of his body, Tali pressed her lips to his in a kiss full of unbridled desire. After half a minute of glorious oral combat between her forked tongue and his regular one, they separated and returned to their previous position.

Shepard was ruthless with his conquest of her ass. He was back to the vigorous thrusting motions that she was used to. The air was filled with the noise of his pelvis clapping against her backside and their collective panting as they fucked like a pair of rabbits in heat. After a few seconds, Tali patted their makeshift bed in a signal to switch positions.

Promptly, albeit reluctantly, the space marine pulled out. Tali sat up, spun around, and gently pushed her adversary onto his back. Then she mounted him in a reverse cowgirl position, a name that she had always found rather funny. Giving her boyfriend a perfect view of her ass, she then lowered herself onto his dick that was leaking pre-cum and throbbing with the desperate need for release.

"Oh, you poor poor thing." Tali hummed as her vagina embraced Shepard's power sword. "So stressed out and full of pent-up energy… Don't worry, I'll give you your Emperor's mercy."

She showed no mercy in how hard she fucked him.

She bucked her hips viciously as she rode him like a White Scars did his war bike. Shepard groaned her name as her muscles clenched around his penis. Tali moaned his name as his penis slammed into her G-spot repeatedly. Until…

Until…

Until…

—-

Until both the Human and Quarian's private parts exploded. Bodily fluids squirted out from between Shepherd's pelvis and Tali's ass as what was the most intense orgasm that both of them had ever experienced ripped out of their body.

"F-F-FUUUUUCCCK!" Tali gasped as she struggled to balance herself. Damn, why the hell did she decide to get on top. She needed to lie down after that. Carefully so as not to break her boyfriend's still-hard cock, she slid off of him and finally let herself fall back onto the bed of Shepard's Captain's Cabin.

The two of them lay there breathing heavily for a few seconds before Shepard reached over and pulled Tali over to him. Their panting slowed as they cuddled over the next few minutes. Finally, Shepard spoke.

"Well… what did you think?"

Tali grinned. "You were right, Shepard. Roleplay really is something else."