Back with another one-shot! I've really gotten into the Criminal Minds fandom as of late, and this idea was knocking around in my skull for quite a while so I couldn't resist writing it. Hope you all enjoy!

WARNING: Implied slash relationship, Arthur/Merlin

Disclaimer: I don't own any of the characters from both Merlin and Criminal Minds.

The light click of the door opening echoed in the confined space of the interrogation room. A man, the FBI agent, quietly stepped into the room, never taking his eyes off the suspect as he shut the door behind him. They were both still for a moment, examining the other, one with contemplation, the other with contained glee.

"Do you need anything?" he asked, his footsteps gentle as he walked up to the table where the other was seated, placing a folder no doubt containing the case file onto the cool metal. "Water, maybe?" He pulled the chair out and sat down, facing the other man with his hands clasped together.

Merlin titled his head. "No," he answered. "I'm fine."

The agent blinked, pausing as his eyes narrowed. "You do realize what you're in here for, don't you Merlin?" he said slowly.

"I killed those people," Merlin said simply, tilting his head to the other side. His tone was so matter-of-fact, filled with his lack of remorse for the actions that led him in here, and it startled the agent. He leaned back, grabbing the file as he did so and opened it, taking out several pictures.

"Morgana Fay," he began, placing a picture of a woman in front of Merlin. The beautiful woman was beaming in the photo, teeth white and sparkling, her green eyes dancing with mirth, her black, sleek hair soft and laid out past her shoulders. "Mordred Drews." A young man this time, looking up at Merlin with a small smirk in place, his flannel covered arms crossed over his chest, looking as care-free as a teenager could look. "And Gwen Thomas." Another woman. Her bronze skin and her curly brown hair were practically glowing in the setting sun as she grinned brightly up at Merlin.

The agent watched Merlin as he examined the photos. When he placed the pictures of Morgana Fay and Mordred Drews in front of him, there was no denying the poorly hidden rage that flickered in Merlin's eyes, or the twitching of his brow as he bit back a scowl. However, when the picture of Gwen Thomas was placed in front of him, Merlin's entire demeanor changed; there was still some rage, but it had quelled down considerably, and his face crumbled for the tiniest second, blinking back invisible tears.

Pocketing this information for later, the agent said, "Why did you kill them, Merlin?"

A silence, tense and heavy, followed his question. Merlin kept his eyes on the photos for a few moments, and when he finally looked back up, his eyes were slack and emotionless, numb and jaded. Merlin smacked his lips and sighed softly.

"You work for the FBI, right?" he asked. His response was slightly croaked, accent deepening in melancholy.

The agent frowned, not missing the fact that Merlin purposefully avoided the question. "Where are their bodies buried, Merlin?"

"The Behavioral Analysis Unit?"

The agent chewed on the inside of his bottom lip, his frustration increasing as Merlin once again evaded his question. He pushed down his growing anger and nodded, replying in a clipped tone, "That's right."

"And you analyze behavior and actions of criminals? Profile them and such?"

"I'm sorry, is there a central question you're trying to lead up to here?" The agent couldn't help but lose his cool for a moment, unable to determine just what it was about this particular criminal that got under his skin. At his mini-outburst, Merlin suddenly smiled, his eyes gleaming with what could only be fond exasperation.

"It's still odd to hear you apologizing," he muttered, an amused hum vibrating from his throat.

The agent's frown deepened. "What are you talking about?"

"You want to know why I killed those people?" Merlin cut in quickly, once again avoiding the agent's question. "Well, you tell me. What did you and your team get? What's my profile?"

The agent scowled. "We couldn't find anything," he said. "No criminal record, no known relatives or acquaintances, no leases, no possessions, no DNA matches, not even a birth certificate. According to our technical analyst, Merlin Emrys does not exist. We only have your word that that is even your real name, and we only apprehended you after you managed to walk in here without being caught by security, cradling the body of Gwen Thomas, and demanding to speak with me and only me." Bitter anger made its way into the agent's voice, his fists clenching and releasing repeatedly.

"And that tells you nothing?" Merlin said, cocking his head once again to the side.

"It tells me that you're probably lying about your identity," the agent answered stiffly. "And that you're completely suicidal, walking into the bureau with the body of a victim who, along with the others, had been missing for a week. You confessed to murdering two others, and remained silent after telling them that you'd only talk to me about where their bodies were. So you don't care about what happens to you, just as long as you talked to me... Why?"

Merlin stared at the agent, keeping their eyes locked together. "What's the word you use to describe what makes a person snap, like, what makes them do things like this?"

"Trigger and stressor," the agent replied. "A stressor would be something in your past, a traumatic event maybe, that has been building up or has affected you your whole life. A trigger would be the thing that actually makes you snap, a direct response that stems from the trigger."

Merlin huffs out a laugh. "Sounds about right... Would you like to hear about my trigger and stressor?" The agent remained quiet, though he arched an eyebrow as an indication to continue. "See, long ago I lost someone very dear to me. Someone that I loved with all of my heart... Do you know what that does to a person?"

"I've seen more than my fair share of people that lost their loved ones and how it affects them," the agent answered, images of serial killers, rapists, lost souls fleeting through his memory. None of these images, none of these memories, were pleasant to recall at all.

Merlin's gaze darkened, and he laughed again, but bitterly this time, not a trace of humor detected. "Not like this. No. Their suffering is nothing compared to mine. I've spent an eternity waiting, wandering around alive while he was dead. I wanted to see him again so badly." The agent blinked but didn't comment on the gender pronoun. "And then... About a month ago... I did."

The agent raised his brows in surprise. "You saw him again?"

A gleeful hysteria blossomed throughout Merlin's face, grinning widely. "Yes. And oh, he was beautiful. Just how I remember him before. He still had that crooked smile, and that arrogant posture of his, always wanting to let others know that he was in charge. His golden hair... It shined in the sun. He was right there, right in my grasp, just across the street from me. But I knew that he wouldn't remember me. After all..." Merlin said, his voice dropped down to a pitiful mutter. "... How would a man back from the dead recognize me, regardless of our time together before?"

It was small, but the agent felt a twinge in his heart from Merlin's speech, crazed as it was, and from the agony laced in his words, tears now clearly evident in his voice and his eyes.

"So... Your stressor was losing him before, and your trigger was seeing him again?" The agent said, feeling the words roll of his tongue as he struggled to interpret the situation. "But I don't understand. How can the return of a loved one cause you to kill three innocent people?"

"They weren't innocent!" Merlin suddenly bellowed, shooting as far forward as the cuffs on his wrists would allow him to. The agent held back a cringe at the rapid change of behavior in Merlin. He had just been lost in the description of his loved one, eyes misty and full of sorrowful nostalgia, the most vulnerable he had been since entering the bureau. And then all of that had disappeared, replaced with a wild fury and crazed blue eyes, almost spitting fire as he glared at the agent. "They weren't innocent! They took him from me!"

"How, Merlin?" The agent said, forcing his voice to keep calm, keeping their gazes locked together, one firm, one furious. "How did they take him from you?"

"They took him... Before." The rage was gone as quickly as it came, leaving the agent with a mild sense of whiplash from these mood swings. Now Merlin crumbled openly in front of him, collapsing back into his chair in defeat, his face crashing down in distress as he stared down at the photos that were still before him. "They took him from me. They took him... They took him..."

The agent pursed his lips together as he watched the grieving man. He sighed as he attempted a different approach. "... Who was he, Merlin?"

A shaky exhale escaped the man, and Merlin sniffed wetly. His jaw wobbled, but he managed a small smile at the mention of his love. "H.. He was right across the street from me." His eyes snapped up then, blue meeting blue as Merlin refused to let their eyes break contact. "He's still right across from me."

Silence, then a numb sort of shock and realization filled the agent as his eyes widened. "Me? You killed those people... For me? But why? I don't even know you!"

A fond look came over Merlin's face, and he chuckled, contrasting with the raw grief in his eyes. "It's like I said, I knew you probably wouldn't remember me, so I was prepared for that. I was just... So happy to see you again, Arthur."

xXx

Aaron Hotchner, Derek Morgan, and Spencer Reid all watched the scene unfold before them behind the glass, and at Merlin's declaration each wore nearly identical confused frowns.

"This doesn't make any sense, Hotch," Morgan said, shaking his head from where he was leaning against the wall, trying and failing to wrap his head around Emrys' delusion. "He saw Penn, and that was what triggered him to kill those three people?"

"Agent Penn is more than likely a surrogate for his actual 'love,'" Hotch answered, his thick brows knit together deeply as he stared solemnly at the suspect in handcuffs. "He lost someone that possibly resembles him, and then when he saw Penn he made the connection in his mind."

Still not entirely convinced that this was the whole story, Morgan turned to look at the youngest agent for his input, and arched a brow when he noticed Reid staring at the ground, face pinched in concentration, thumbnail in his mouth. "Reid? What's up?" Morgan asked.

"Arthurian legends," the young doctor answered in an almost dazed mutter. Slowly, he glanced up, his brown eyes widening, an idea clearly forming in his expression. "Guys, this may sound completely ridiculous, but I don't think this was something as simple as a surrogate."

"What?" Morgan said, pushing away from the wall. "You can't possibly be telling me right now that you believe his story right? That Penn is his long-lost love back from the dead, somehow having resurrected, and that's what caused Emrys to go postal?"

"I'm not saying that, of course not," Reid waved away Morgan's response. "But think about this. The Arthurian legends: there's King Arthur Pendragon, and there's Arthur Penn; Queen Guinevere, Gwen Thomas; Morgan Le Fey, Morgana Fay; Mordred; Merlin the warlock, and Merlin Emrys. The parallels between the legend and this case are astounding!"

"Well, you're right, kid," Morgan nodded. "That is ridiculous."

Hotch, however, looked quite interested in Reid's forming theory. "So this could be a reenactment of the legend perhaps? What else does the legend say?"

"There are many variations of the story, but all in all the basics exist in every one," Reid continued, approaching the interrogation window. He pointed at the criminal tied to the table in handcuffs across from Arthur. "Merlin was absolutely devoted to King Arthur, he loved him and protected him. Morgan Le Fey, King Arthur's half-sister or lover depending on the story, and Mordred, her son in some variations, were the main components that led to Arthur's downfall and death. Merlin would have been distraught, completely devastated over the loss of his king."

"Morgana Fay. Mordred Drews," Hotch muttered, rubbing his forehead, soothing down the lines that had long since formed there. "Not exactly common names, especially around this time era."

"Seriously?" Morgan questioned. He had always been a strong skeptic to these sort of ideas that popped out of Reid's mouth during their cases.

"I'm not saying that they're the legit characters from the legend, after all it is still a legend. But you have to admit, Morgan, there are way too many coincidences for this to not be at least a little weird," Reid replied.

"Well, even so, what about Gwen Thomas?" Morgan said, resigning himself to the fact that Reid wasn't going to quit this theory. "Judging by the legend, she'd represent Queen Guinevere, right? Arthur's wife? Why did he kill her?"

"Queen Guinevere was widely known for her affair with Sir Lancelot Du Lac, the most noblest of knights of the Round Table," Reid answered. "Some versions of the tale would have Merlin openly displaying his disapproval of her actions... or maybe this was jealousy? Emrys said 'They took him from me...' When he glanced at Morgana and Mordred's pictures, he was clearly angry, and there was no regret at all. But once Penn put Gwen's picture in front of him, his entire posture changed: he sunk into himself, almost looking shameful and remorseful."

"So he didn't want to kill her," Hotch cut in, still staring inside the interrogation room. Penn was now gathering the photos and placing them inside the file. "Perhaps she stood in the way of him reaching his 'love,' an unfortunate obstacle that he had to get rid of, no matter how little he wanted to."

xXx

There was only the sound of shuffling paper as Arthur Penn replaced the photos into the case file. Slowly, he closed the file and leaned back in his chair, placing a hand on the table. He drummed his fingers softly against the metal surface before he spoke again. "Where are their bodies, Merlin?"

"Authoritative," Merlin said, his eyes sparkling as he smiled. "You know, an FBI agent... It suits you. Might not be the same as king, but it does the job nonetheless."

Arthur's eyes narrowed but he didn't ask for further elaboration. "Where are their bodies, Merlin?" he repeated, firmly enunciating his words, a stern glare set on the man before him.

And once again, Merlin evaded the question, still watching Arthur, still with that devastatingly adoring smile on his face that caused unpleasant shivers to travel up Arthur's spine. He was quiet for a long moment, his smile faltering and fading until it was no more than a thin line, his shoulders slumped. His eyes continued to sparkle. "They were going to take you again," Merlin whispered. "And... I couldn't allow that to happen. I love you so much, and..." His voice trailed off as it cracked, and he sighed, sniffing. A glimmering tear trailed down his worn face. "...You'll eventually remember. And they would have too. And once they did... I couldn't let that happen. Never again."

A second tear followed the first, and Arthur watched silently as Merlin struggled to regain his composure.

Eventually, he spoke again, in a voice more broken and more tired than that of any other person Arthur ever met, "... They're in the lake. The one off Little Road."

It took him a moment, but Arthur managed to stand slowly from his chair, grabbing the file on his way out. He made it to the door, his hand grasping the handle before a whisper behind him halted his actions.

"Arthur?"

He hesitated, then glanced over his shoulder. A ghost of a smile tugged at Merlin's lips, but the rest of his face screamed agony and despair. "I-I hope you can find it in your heart to forgive me. For this... And for the rest." The question must have shown on Arthur's face, and Merlin chuckled sorrowfully, tears now openly trekking down his face, dripping from his jawline onto his shirt. "I told you. Eventually, you'll remember. And when you do... Please forgive me."

The desperation in that simple plea followed Arthur out of the room. He closed the door gently behind him, barely taking note of the light trembling in his hand. Sighing, he closed his eyes, rubbing the bridge of his nose between his thumb and index finger.

"Penn?"

Arthur looked up and came face to face with Reid and Morgan standing before him in the hallway. He cleared his throat, willing a calm composure in the face of his teammates, and said, "Hotch is on his way, then?"

"Got Prentiss, Rossi, and JJ to go with him," Morgan answered in verification. "Hopefully, Emrys is telling the truth, and they'll find their bodies. Give the families some peace of mind."

Arthur nodded, glancing down at the tile floor. "Good."

"You alright?"

This time it was Reid who spoke. Biting his bottom lip, he nodded again, looking up into the concerned face of the young doctor. "Yeah, I'm fine. That was just... Different. There's something about him... Can't quite put my finger on it."

It was very brief. Probably lasted for only a split second, and for one fleeting moment, it wasn't Reid's face in front of him, but instead Merlin's. Definitely Merlin, staring defiantly at him, wearing a worn cotton tunic and brown trousers like something from olden times. His voice echoed in Arthur's mind, cutting through the reality of his memories with a light stab of pain.

"How long have you been training to be a prat, my Lord?"

Arthur blinked. And then Merlin was gone, and a sympathetic Reid was in his place again. There was no indication that either profiler in front of him noticed Arthur's momentary lapse in focus besides Morgan's quirked brow. He cleared his throat again, more roughly this time.

"Yeah," he muttered, turning and walking down the hall, away from Morgan and Reid, away from the interrogation room containing Merlin. "Something about him."