Title: The Alien Within

Summary: There's an alien within him that he can't control. One day it's going to break free and he can't do anything to stop it.

Word Count: 2,949

Disclaimer: I do not own Grimm or any of its characters. I am merely borrowing and using for my own purposes.

Author's Note: This is written for the Fanfic Challenge over on the LJ community Grimm Challenges. The Challenge was a word association, the word being Alien.

oOo

"So, do you have a crush on her or do you just find her as beautiful as I do?" Nick asked the man he'd managed to corner in the office. His tone was meant to sound friendly and off-hand, but the man could hear the anger that lay just beneath.

Captain Sean Renard stood behind his desk, staring calmly at the detective-turned-Grimm. He was doing his best to appear laid back and unconcerned, but he could feel the anger of the Grimm boiling under the surface and the hexenbiest within him was scratching, begging to be let out and respond to the assumed threat.

When he continued to lean against the filing cabinet behind his desk, all but smirking at the detective, Nick continued on, "I saw the way you were looking at her at the awards ceremony, so I thought I'd throw that out there to get the uncomfortable part over with."

"And what makes you think that you saw what you think you saw?" Sean returned, not willing to admit to anything. If Nick found out exactly how connected he was to the Grimm's life and what had happened in it, things would not go well, for either of them.

Nick chuckled, anger coming through each short breath. When he began to pace, Sean felt the hexenbiest begin to do the same, mirroring the Grimm's furious posture. After a few seconds of pacing, Nick turned on the spot and opened his mouth, but no sound came out. It was clear he was trying to organize his thoughts into something that wouldn't be so accusatory that he couldn't talk his way out of it. When he obviously failed to come up with anything, he simply shook his head and walked out, making sure to slam Sean's office door as hard as he could on the way out.

The Captain watched his employee leave, his muscles twitching, almost aching to act on his current anger, but he held back. The Grimm was too important to his plans to give anything away, even if it meant he had to suffer a little as well.

oOo

Weeks passed yet Nick never mentioned Sean's attraction to his girlfriend again. Sean knew that the Grimm still thought about it, however, because there were times he could feel the man watching his every move. For his part, Sean did his best not to think about Juliette Silverton, but it turned out that the more he tried not to think of her, the more he obsessed over her.

A commotion sounded from the doorway to the department, making Sean look up only to see Detectives Burkhardt and Griffin hauling a rather raucous and unwilling suspect towards the interrogation room.

Hazel eyes drifted over to the Grimm, watching his grim determination with interest. Nick's left hand was clamped rather firmly on the suspect's bicep, the strength of his grip showing the white in his fingers. His jaw was clenched in what appeared to be anger, but upon closer inspection, the obsessive part of Sean was happy to discover that it was actually pain. Sean had a second to let the disgust at his own delight wash over him then the more controlling side came back and reveled in the information.

Two bruises decorated Nick's face, painful-looking and livid. The worst of the two had settled itself onto the Grimm's right cheekbone, sneakily snaking up towards his eye. The other rested in the top corner of his forehead, just below his hairline; unlike the one on the cheekbone, this one had a scratch at the center which appeared to be still dripping with blood. As he walked, Sean noted a slight limp in Nick's gait, but he couldn't tell which side.

Now's your chance, a voice whispered, cooing into Sean's ear like the devil it was. The Grimm's weak; he couldn't defend himself now. Take him and then Juliette can be yours, forever.

Pain throbbed through Sean's head as flashes and images of Juliette shot through his memory, blinding his vision. He put a hand to the bridge of his nose, hoping to stifle the pain and the images.

"Captain?" Detective Hank Griffin's voice interrupted, catching his attention just in time.

In a split second, Sean swallowed down the wesen side, shutting it behind an iron door which he hoped would hold it in an attempt to be himself again. He looked up at Hank and waited for the detective to speak again.

"We've got the suspect in custody," Hank began, but he stopped when he saw Nick coming towards him with a paper in his hand. The Grimm held it out to his partner and waited with a strained smile while he read it. Forgetting that they were both standing in Sean's doorway, they shared a private moment.

"He confessed?" Hank asked, not bothering to mask the surprise in his voice.

"Yep," Nick answered happily, leaning against the opposite side of the doorway as Hank. He crossed his arms over his chest and threw his left leg over his right, thus putting all of his weight on his right side.

There, the voice spoke again. It's the left leg that's injured. Now you know your point of weakness and where to attack when you're ready.

No! Sean snapped at the voice, willing this newer, alien side to disappear so that he could continue with his plans for the future.

Oh, come on, the voice whispered, slithering into his mind like a poisonous snake. It would be so easy. Sean felt the hexenbiest lick its lips at the prospect of the violence and blood, he felt the thing practically shivering in anticipation. And then Juliette will be yours for the taking.

Sean hissed as another burst of pain shot through his head, once again accompanied by images of Juliette, this time in compromising positions.

"Captain, you alright?" Nick asked as the admission of pain caught his attention. The Grimm straightened up, wincing as he put his weight on both of his legs and edged forward in what appeared to be concern.

Sean smiled and waved off their concern, smiling more at the expertly faked emotion coming from the Grimm rather than his desire to appease his detectives' worry. He knew that Nick's way of seeing him had changed the night he'd accused him of liking Juliette and so he knew that Nick wasn't worried so much as assessing him.

"I'm fine," Sean assured when the two detectives continued to look at him warily, "just a headache. So he confessed to the murder?"

"Yeah," Nick answered, appearing to make sure he remained upright so that he looked stronger than he actually felt. "I think he's hoping to get the insanity plea."

"Well he's got my vote," Hank said, coming to stand next to his partner. "The man is crazy."

Sean nodded, showing them that he heard but had nothing to truly say. "Good," he said, settling for the simplest thing. "Hand this over and then go home; you both look like you could use the rest."

"Nick more so than me," Hank said, half under his breath, half not.

Nick looked sharply at his partner, as though sending him a warning for saying anything. He looked over his shoulder at Sean, sighing when he saw that the Captain had his eyebrows raised in an expression of interest.

"I'm fine," he said somewhat unconvincingly when he added a small wince to the sentence. "I'm just a bit banged up."

"'Banged up'," Hank scoffed, rolling his eyes. "He got knocked around a few times. Good thing he has a thick head."

And with that, the two partners walked out of the office, trading jibes at one another as was their way when it came to their friendship. He knew that they were hiding something from him – like how getting knocked around meant Nick had a limp – but he couldn't throw stones given how he lived.

Sean watched them leave to go home, his hazel eyes stalking the Grimm out of the door, waiting for his opportune moment.

oOo

Nick pulled up to the house, sighing heavily. The house, which had once been so warm and bright, now looked cold and abandoned. Though Nick and Juliette still lived inside it and kept it up, the sense of home had long gone. Ever since Juliette had come home from the hospital, they'd both felt like strangers – not only with each other, but with the house which held so many of their loving memories. It felt as though, not only did Juliette not know him anymore, but the house didn't recognize either of them and that felt like a stone in the stomach.

Tonight, the inside was dark - the only evidence there was that Juliette wasn't there. He leaned his head back, dreading the idea of walking into an empty house. His head gave a particularly violent throb, making him drop his head forward with a groan of pain.

The suspect had gotten the drop on him tonight. He'd felt that there was someone behind him, but he hadn't been quick enough to do anything about it. It helped to soothe his pride to know that it was a lowen – a race known for their ability to stalk and surprise - he'd been up against but it didn't help the migraine of a headache or the throbbing in his knee from where the wesen had powerfully knocked his knee out from under him.

Resigning himself to another night of cereal for dinner, Nick put his hand on the door handle and got out. His feet hit the ground with his left one collapsing under the sudden strain of his weight just as his phone chirped that he had a text message. He was about to ignore it when he saw that it was from Monroe.

Need help at park across from my house.

That was all it said, and while it was enough to get Nick back into his car, it still had him both worried and suspicious. He could have sworn that Monroe was still at the Spice Shop, subbing for Rosalee, so why did he need Nick's help at his house? No, not his house, the park across from his house – well, that didn't make anything any better. Deciding it was best to be safe rather than sorry, Nick decided a trip to Aunt Marie's trailer was in order. That way, if something else was trying to surprise him, he'd at least have the appearance of being ready.

oOo

Snow had started to fall in the park, laying a gentle blanket of white over the green and brown to give a look of innocence.

Innocence that was about to be ruined by blood, he thought grimly as he waited for Nick to show up. Taking the blutbad's phone had been a simple matter of sleight of hand since the wolf had left it lying around on the Spice Shop's counter, and Sean knew that Nick would answer the blutbad's request for help so he'd taken advantage where he could.

The rumble of Nick's truck sounded just to Sean's left and so he readied himself for the fight that was about to ensue – the fight that would result in the Grimm's death.

He waited in the shadows of the trees, watching as the Grimm slowly made his way up the slope of the hill and then coming to a stand-still in the middle of an outcropping – right where Sean wanted him to be. Without bothering to think of the consequences of what he was about to, Sean leapt forward with a ferocious snarl.

Nick looked startled, pivoting to his left in time to receive the full blow of Sean's attack. They landed on the ground with simultaneous thuds where Sean refused to get off, snarling, snapping and scratching every bit of the Grimm he could find. He howled when he felt a prick of something small yet sharp, quickly followed by immense pain.

"Monroe told me that you'd stopped by for a cure for obsession," Nick growled out, slightly panting as he rose to his full height. "He says that this should help bring you back to your senses."

And with that, Nick attacked, barreling into Sean with a strength the royal didn't know the man had had. He knocked Sean to the ground, pinning him there while holding Sean down to wait for the serum to take effect.

With a burst of strength born of desperation, Sean threw Nick off him, flinging him ten yards against a tree. Nick landed in a pile of bushes, flattening them in seconds with his weight but he was up in an instant. He didn't look particularly steady on his feet, but Sean didn't let that fool him – there was a fierceness in his Nick's eyes that could only be associated with the spirit of a Grimm.

The two men charged one another, coming to meet in the middle of the clearing with painful force. Since his height and weight were bigger than Nick's, Sean's momentum had them both flying backwards to where Nick had just come from, landing on the ground where Nick grunted in pain.

"You are mine, Grimm," he said in a voice he barely recognized as his own. He reared back to take a bite out of the Grimm, preferably right where his jugular is, only to head butted by said Grimm and flung off with the same strength he'd witnessed earlier.

"I don't think so," Nick said. He pulled out something long and small and shoved it into his own arm. This action confused Sean because it was clearly a syringe but why would the Grimm be injecting himself? Unless it was something to make him last longer, in which case the blutbad could have whipped something up, but that wasn't Nick's style.

In a flash, Nick was charging at Sean once again, this time using the surprised he'd caused to his advantage and bowling the royal over.

"This should help you feel more like yourself," he said before stabbing Sean with the same needle he'd just shoved into his own arm. As agonizing pain raced through Sean's veins and he tried to fight the oncoming darkness, he could only recognize one thing – this was how Adalind felt.

Huh, he thought as he felt himself slipping away, paybacks are a bitch.

oOo

Ugh, he felt groggy. Worse than groggy actually, he felt hung over which he knew wasn't right because he knew he hadn't been drinking.

"So," said a raspy, yet overly cheery voice to his right, "how are we gonna explain this one?"

Sean opened his eyes to slits and turned to look at the very beat up Grimm sitting next to him. Every new bruise, scratch or scrape made him wince with guilt. He didn't know how he'd ever keep Nick in Portland now; not now that the Grimm knew a portion of what had been going on.

He sighed, turning his head away so that he could try and think but no answer came. No solution, no quick fix that would make the past few months disappear so that they had never happened.

"Right," Nick said, taking Sean's turning away as a dismissal. Yet, instead of leaving like he ought to have done, he simply shifted in his seat. "I'm thinking aliens, but I was wondering if you thought that would be too extravagant."

Sean turned to stare at the Grimm, dumbfounded by his attitude. The royal had just done his damnedest to kill the man, not to mention creepily stalking his would-be or once-was girlfriend and he's making this all a joke? Seriously?!

"'Cause it's not like we can tell them the truth – that you woke my girlfriend up from a coma and then later became so obsessed with her that you wanted to kill me to get her – I'm not thinking that's going to fly too well for a lot of reasons."

Now Sean saw it. Beneath the joking façade was an anger that was boiling so hot it lit up Nick's blue eyes to a dazzling colour.

"Sorry about the whole killing-the-hexenbiest-thing, by the way," Nick continued, shifting in his seat so that he could stand. Along with the new bruises and scratches, he now adorned a bandage over his wrist and a brace over his knee, to say nothing of the wrapping that probably covered his side which was judged solely by the way he was carrying himself.

He stopped by the door and pivoted, somewhat stiffly and painfully. "I guess that makes us even." He paused, seeming to think that over and then added, "Or maybe it doesn't since you also tried to kill me."

So, he knew that Sean was behind the murder of his aunt – great. Refusing to admit or acknowledge anything, Sean looked to the ceiling, waiting for the Grimm to leave. When he didn't, Sean looked over and asked the only thing he could think to say.

"Why am I in a bed and you're not?"

"I guess you're more delicate than I am," Nick shrugged, his cold smile telling Sean exactly what he thought of the royal. He breathed in as deeply as he could and then sighed, as though breathing in the fresh air that Sean wouldn't get to see for a while. "Yeah, I'm thinking aliens. Aliens are always responsible for something, aren't they?"

And with that he left Sean alone in his hospital room to contemplate what he'd do without a Grimm on his side.

~fin~