A/N: So, you know how there are all those Reaper!Bones stories where Reaper eventually takes the identity of Leonard McCoy? Well, one day I made the mistake of wondering, "Gee, what would happen if the transition went in the other direction?"

The result was this ass-backward Reaper!Bones fic. Why is it not in the Crossover section? Well, because it's pretty much set within the Trek canon, and that which was borrowed from the Doomverse has been mangled almost beyond recognition. Herein you will find no John Grimm, no C-24 enhancement, and no long centuries of angst. You will find the RRTS Marines, Olduvai's Imps, and a seriously badass Leonard McCoy. Oh, and an implied threesome that I wasn't actually expecting.

This was originally intended as a multi-chapter fic; unfortunately, the bunny that inflicted it upon me immediately fled the scene of the crime. However, I think it stands fairly well on its own - and honestly, I'm just too damned fond of the concept to delete it.

2260, September

"Our Father who art in heaven, hallowed be thy name. Thy kingdom come. Thy will be done, on earth as it is in heaven. Give us this day our daily bread, and forgive us our trespasses, as we forgive those who trespass against us. Lead us not into temptation, but deliver us from evil—"

Goat's prayer was interrupted by an agonized shriek from just outside their makeshift bunker—one that was almost, almost human, and Leonard "Reaper" McCoy was willing to bet that every hard-assed son of a bitch holed up in there with him had flinched in the dark.

Deliver us from evil, indeed.

"Amen, Goat," he muttered, needing no light to finish reassembling the modified G36P assault rifle that seemed more like an extension of himself with every week that passed. The stock slid into place with a familiar click, the sound practically a benediction in the sudden and unnerving silence. "A-fucking-men."

"And if we get out of here alive, I'm already in fucking Tahiti, because that honey at the Coco Cabana was one fly piece of ass," Duke added.

They each had their own prayers, for nights like that one.

2262, May—Present Day

When the transfer order came across, Dr. Leonard McCoy didn't challenge it, despite the fact that he'd only been back on the right side of the hospital bed for two weeks. He hadn't been able to win an argument with Chris Pike even when the man was just attempting to recruit a prematurely washed-up divorcé, and nothing he'd experienced in the intervening seven years suggested that his luck had changed. The situation was becoming an embarrassment to the 'Fleet, he was informed—or at least, to Starfleet Medical—and since Leo had a proven record with this particular problem child, he was clearly the solution. Case closed, so far as Admiral Pike was concerned.

So it was that when the Enterprise came sulking back into spacedock with her seventh CMO in just over three years already screaming for reassignment, Leo was waiting at the 'port to relieve the frazzled woman, misgivings in tow.

He couldn't say no to the Enterprise any more than he could say no to Pike. Although he hadn't served on it in three years, it still glowed warmly in his memory as the closest thing to a home he'd had since the divorce. His year on the Enterprise had been a good one; maybe even the best in his life.

It had also ended incredibly fucking badly, and he figured that he was going to pay for that in full now.

The shuttlecraft docked, and Leo shook hands with the outgoing CMO—a thoroughly capable-looking, gimlet-eyed matron who was practically weeping with gratitude. Waving off her well-intentioned but somewhat incoherent warnings, he boarded in her place, a single duffel bag thrown over his shoulder. He gave the unfamiliar pilot and copilot nods of acknowledgment, but didn't try to initiate conversation.

More unexpectedly, neither did they. His suspicion that the ship's gossip mill was already hard at work—and that it hadn't judged in his favor—strengthened exponentially. His jaw tensed as he strapped himself in and braced for impact.

For once, it wasn't the shuttlecraft that he was worried about. His hands flexed unconsciously, uncomfortably empty.

xxx

Gaila was as shocked as anyone else to hear that Dr. McCoy had accepted a transfer back to the Enterprise—and that Jim had approved it. Professionally, the doctor's reputation was tarnished by the vanishing act he'd pulled three years ago, even if the brass had apparently supported it. The bad blood was even more bitter among those who'd considered themselves Leo's friends, but had received nothing but silence from the man for those same three years. None of them would ever have suspected that the practical doctor would take his reaction to a silly rumor to such extremes; especially not the man who had shared his bed, and thus inadvertently started said rumor.

The same man who was currently waiting near her station at the shuttle bay controls with his arms crossed over his gold command tunic, his normally open expression shuttered tight and his blue eyes stormy.

Though Gaila's naturally cheerful disposition didn't promote vindictiveness, she couldn't help but entertain the thought of Leo stumbling off the shuttlecraft, white and shaky as always, to greet his captain with his usual careless salute. She fully expected Jim to put him in his place like the hand of the Highest Deity. She was even looking forward to the confrontation with a sort of anxious anticipation. Judging by the unobtrusive audience that had gathered, she wasn't the only one.

The moment the man in question stepped out of the shuttle door, however, she knew that the reunion wasn't going to play out as expected. Though his full lips were pressed into a tight, pale line, there was no sense of disorientation about him, no annoyed exclamations or wild gesticulation. Instead, he appeared both aware and wary, seeming to survey and analyze the entirety of the bay in the barely perceptible pause before he began the long, exposed walk to the inner doors. Though Gaila was reminded, rather bleakly, of old Terran films showing men en route to the gallows, his stride was smooth and brisk. His gaze met that of James T. Kirk unerringly, and with an equal lack of hesitation.

As he drew nearer, Gaila cataloged the changes in his appearance with increasing unease. His dark hair had been cropped to about an inch from his scalp. Too short for the fine strands to lie flat, it stood up in as many places as not, acquiring an oddly soft but spiky look. The raised, pale line of a scar traced his left cheekbone, and she winced in sympathy; with modern dermal regeneration techniques, it took vicious damage to leave such a visible scar. His face itself, and what she could perceive of his body beneath his medical blues, was leaner and harder than she remembered—and since he'd been Jim's roommate back at the Academy, she had more extensive knowledge of his physique than would otherwise be probable.

She'd spent more than one night in their room, during those days. And people could make what they would of that.

The overall effect wasn't unattractive, by any means. In truth, he looked rakishly handsome…and a little dangerous. And that bothered her more than she could express. Dangerous wasn't a descriptive term she would ever have applied to the Leo McCoy she'd once counted as a friend, and more.

She brought her regard cautiously to his hazel eyes, afraid of finding them hardened, as well. Though darker and more wary than she'd ever seen them, they were not. Her sigh of relief twisted in her chest when the accurate adjective came to mind.

Haunted. Whatever Leo McCoy had been up to in his absence from the Enterprise, it had left him scarred, and haunted, and carrying an edge that should have been completely foreign to his nature. Gaila shifted from unease to flat worry, her disappointment in her old friend all but forgotten.

He stopped a precise two yards in front of Jim, snapping to full attention. She saw Jim startle slightly in her peripheral vision, but he recovered with alacrity.

"At ease, Commander." Though Jim's voice gave nothing away, it was Gaila's turn to be startled. She looked more closely at Leo's sleeve and discovered that it did indeed bear the stripes of a full commander, rather than those of a lieutenant commander as it had upon his departure. Her puzzlement was only compounded as Leo shifted into parade rest with an easy grace that she never would have granted him, before.

"Commander Leonard McCoy, MD, reporting for duty, sir. Permission to come aboard, Captain?"

"Permission reluctantly granted, Dr. McCoy," Jim replied flatly, though irony heated his tone with his next statement. "I'll do you the favor of being upfront and honest about our situation." Jim's mouth twisted into a grim smile around the silent addendum, the way you weren't. "I argued against your reinstatement. Unfortunately, I was overruled."

Gaila winced again. It wasn't like Jim to speak so disparagingly to an officer in public, no matter what his personal opinion of the individual in question. She sincerely hoped that Spock, at least, would be able to find enough personal distance to discuss the matter with Jim before it became a habit.

Frankly, that just wasn't a conversation that she wanted to have with her captain and lover. Especially not about this particular officer.

Although his eyes flashed, Leo took the insult stoically. "Duly noted, sir. I had already been made aware of the Admiral's…interest, in the situation." The sinking feeling that this careful response initiated was compounded by her sudden realization that the soft drawl which had always colored the Southerner's speech was completely imperceptible, his enunciation crisp and standard.

"Dismissed," Jim finally said, after a pause just long enough to make her wonder if he'd noticed the same thing. "Yeoman Rand will escort you to your quarters."

The doctor tossed off another impeccable salute before turning to follow the blonde Yeoman, leaving Gaila to lock dismayed eyes with a clearly bewildered Jim Kirk.

What the hell had happened to Leonard McCoy, after he left the Enterprise?

2259, March

Leo would always remember thinking how incredibly stupid the fight that drove him outside that evening was.

"You realize that everyone thinks we're sleeping together, don't you?" he'd asked, tone a little too sharp. They'd been borderline snappish with each other all day, the little things rubbing each other wrong in the way people who've lived together for several years sometimes do.

"We are sleeping together, Bones," Jim had replied, all amused annoyance.

"Literally, sleeping. That's not how the rumor mill would have it, though."

"Well, it's not like we never have," Jim pointed out, shrugging. "Who cares what they think, anyway?"

"I do, obviously," he snapped, troubled by a question that he couldn't quite put his finger on. Jim didn't give him the chance to elaborate, though.

"Shit, Bones, would you listen to yourself?" he snapped back, rolling his eyes. "You sound like a little schoolgirl, bitching about her rep on the day after prom night. Get over it, already!"

Stung, he'd walked out of the rented cabin where they were enjoying their first Earthside shore leave in over a year without another word. He wandered aimlessly for a few minutes, his hands in his pockets and his eyes on his feet, with the result that he actually found himself several yards inside the twilit woods surrounding the cabin by the time the elusive thought finally became clear.

He'd kind of been hoping that they would figure out where their relationship stood, themselves, before other people started analyzing it for them.

He didn't get the chance to dwell on the revelation, though. Two shadowy figures barreled out of the woods, and he threw himself out of their path instinctively.

The larger figure resembled nothing so much as a horror movie demon, with shriveled, mushroom-pale skin, slathering fangs, and vicious claws. Almost before he'd dodged out of the way, it had literally picked up the smaller figure—actually a black man larger than Leo himself—and thrown him at Leo's feet.

"Shit!" he yelped, dropping to his knees beside the injured man as the creature's head and chest exploded. Pulse phaser fire, eerily silent, originating from a second human who had emerged from the gloom.

"Status, Duke!" the newcomer barked out as he jogged into speaking range. The late afternoon sunlight limned the tall man's bronze skin and shaved head in gold; a specious halo, to be sure.

"I'm okay, Sarge," the downed man coughed out, struggling to rise.

"The hell you are," Leo muttered viciously, planting a hand in the middle of the man's chest to keep him in place, while the man's gun slipped from fingers that were spasming with pain. But as Leo reached for the ever-present tricorder in his coat pocket, four more monstrous forms skittered out of the trees.

All three men cursed violently, the tall one—Sarge—scrambling to raise the weapon he'd paused to recalibrate. Leo rolled into a defensive position in front of the downed gunman, scooping up the abandoned rifle as he went. The motion wasn't as foreign as most people who knew him would have expected it to be. He had basic weapons training, and an aim he'd been downplaying for years to get overenthusiastic Starfleet instructors off his case.

It came back to him as naturally as it always had—move with the weapon, breathe with the shot. The exquisite physical control and hand-eye coordination that served him so well in the surgical theater were an equal boon in this. He lined up and squeezed off faster than the other man; four clean head shots, while Sarge finished off the bodies with his higher-powered weapon.

"Goddamn," the injured man, Duke, wheezed out, looking at him with new consideration. He licked his lips uncertainly, then continued, "Always double tap with the Imps, man. Head, then heart. Second rule."

"Why, are there more of them?" Leo asked, his voice a harsh whisper.

It was Sarge who answered. "No, only the five. In this pack."

Leo glared at him before thumbing the safety on the assault rifle and setting it down, returning to his patient before they completely lost the light. "What the fuck are you telling me for, then? I'm a doctor, not a goddamn sniper!"

The readings that registered on the tricorder, before he specifically tuned it to the bleeding human, arrested his total, shocked attention for a moment. As a result, he missed the skeptical look that passed between the two men. A low hum from the earpieces he hadn't noticed either man wearing recalled his attention, however, as Sarge tipped his head, listening intently.

"Ten-nine, Destroyer, I didn't copy." He paused, his scowl deepening, then clearing. "Ten-four. We're clear. Send in the cleanup crew." He paused again, expression thoughtful. "No. And call the boss."

He strode over to crouch by the pair on the ground, laying a hand against Duke's sweat-damp forehead. "How's my soldier, doc?" Leo glanced up from his attempts to staunch the man's bleeding, lifting a brow at both the phrasing of the question and the intensity behind it.

"Clawed up with busted ribs," he said, bluntly, "but by some miracle, there's no internal damage."

"Lucky bastard," Sarge noted, and Duke gave him a weak one-fingered salute, trying to rise again. Leo pushed him back down, slightly less gentle than before. He didn't enjoy the man's soft gasp, but it made his point.

"Stop. Moving," he ordered. It earned him another considering look.

"So, doc," Sarge began, and his carefully casual tone set Leo's teeth on edge.

"So, Sarge," he drawled back. "Black ops, yeah?"

The man frowned at him. "Why would you assume that?"

Leo leveled a glare at him. "Are most of the people you associate with really that stupid?" Duke choked off a laugh with a quiet moan, but Sarge's frown simply deepened. Leo closed his eyes and sighed. "Because you're shooting up formerly human monsters equipped with synthetic chromosomes in the goddamn backwoods of Oregon, using heavily modified weapons, apparently with every intention of erasing the evidence. And you're desperate to get your boy out without involving the local EMS." He opened his eyes and met two shocked faces with a humorless smile. "That is what you were about to ask me, isn't it? Seeing as I'm already in deeper than either of us would like."

"I've got no fucking complaints," Duke muttered. They both ignored him. Sarge was observing Leo carefully, measuringly. When he suddenly found the man's phaser pointed at his head, Leo understood why.

The wary sergeant had seen his intention to run almost before he'd finished making the decision.

"It's a little too late for that, doc," Sarge informed him, not without regret. But underlying that was a flat determination that made Leo narrow his eyes at the larger man across the phaser barrel.

"It's like that, huh?" The rest of the "cleanup crew" had evidently arrived—Leo was aware of at least three more weapons trained on him, and a silent Asian man had retrieved Duke's discarded rifle.

"Out of all of our hands, really. But yeah, I'm pretty fucking sure it's like that."

"Then hand me your goddamn med kit and get the hell out of my face," he growled, never letting his glare waver. For a moment, the man's expression and trigger finger tensed, and Leo braced for the denouement. But before it came, a braying laugh broke the moment.

"Damn, Sarge. Please tell me you're gonna rip this civvy a new pussy!"

"Dunno, Portman. Seems like a shame to waste that kind of brass," a deep, new voice rumbled thoughtfully in response.

Sarge seemed to hover on the precipice for another moment, tempted. But then he shook his head and holstered the phase pistol. "Destroyer's right." He looked pointedly at the downed monsters. "And I seriously doubt this one's a civvy."

Duke looked up at him intently. "Seriously, dude? You 'Fleet?" Something in his expression must have given him away, because the injured man crowed in excitement, then gasped, then coughed, and somehow still managed to begin an enthusiastic recounting in the midst of it all. "Shoulda seen it! Handled that rifle like some kinda grim-fucking-reaper, man—cut those bitches down before they even knew what hit them! And he's a fucking doctor, too. Smart one. Didn't even have to tell him about the C-24." Duke grinned up at him, eyes actually shining with mirth. "Your ass is so ours, doc."

By the next morning, that prediction had proven distressingly correct. Starfleet did own his ass—and they handed it over to Gunnery Sergeant Asher Mahonin of the Rapid Response Tactical Squad upon request. Apparently, keeping an ancient Martian genetically engineered zombie plague from wiping out all humanoid races trumped serving as CMO of the flagship, because the decision was absolute. Equally apparently, the fact that Leo technically outranked the NCO got lost in the...unusual nature of his transfer.

Until such a time as time as the mess he'd so inadvertently stumbled into was resolved, Lieutenant Commander Leonard McCoy had officially been commandeered by Starfleet Special Forces.

His code name?

Reaper. The irony was far from lost on him.