One of the lesser-known dangers of taking a degree in Classics is that you start thinking of your Ancient Greek textbook as an appropriate source of inspiration for your anime slashfic. For those interested, 'protasis' is a linguistics term referring to the 'if' clause in a conditional sentence. In other words: "If Byakuya and Renji hooked up, it would be pretty hot." And, um, I swear the title is the only linguistics reference in this fic. So please don't judge me too harshly.

This is set between the Fullbringer arc and the Thousand Year Blood War arc. There will be three chapters in total; anyone who's here just for the smut should look to chapters two and three, when they are posted.

To the casual observer, the scene would have appeared chaotic. The earthquake had torn the town apart from its foundations, leaving in its wake shattered ruins of buildings and the bodies of its many victims. Relief teams scampered through the rubble, tending the wounded and scouting for further survivors.

To the less casual observer – one, perhaps, with a little more spiritual strength – the scene would have appeared almost twice as chaotic. A large number of pale, confused-looking souls milled around, and sometimes straight through, the rescue workers, thick metal chains protruding from their chests and setting off an awful chorus of clanking. These souls were being tended to by a team of black-clad soldiers, similarly unnoticed by the rescuers, who spared them not so much as a glance. Adding to the chaos were a number of what could only be fairly described as monsters, gathered at the scene of the disaster like hungry vultures and attempting to attack the frightened spirits of the dead. These were being warded off by another team of soldiers in the same black uniform.

In the midst of this pandemonium, our casual observer might have noticed a strange pair of men picking their way lightly through the rubble of what had once been a fashionable shopping strip. One wore a white haori over the standard black uniform. He had a handsome, haughty face, with heavy-lidded eyes and thick lashes, framed by shoulder-length black hair. His companion's hair was an improbable shade of red, worn in a thick ponytail. Black tattoos mapped their way across his forehead and, going by the glimpses of skin allowed by his uniform, the rest of his body as well. The striking appearance of the two was lost on the rescue workers, who seemed unable to see them.

It was not, however, lost on the recently deceased Saito Hiroshi, aged seventeen, whose shift behind the register of a popular fast-food joint on that very strip had been cut short when the building collapsed. Surprised to find himself still conscious post-mortem, and unsure how to proceed, he had sat down beside his own lifeless body and tried to remember what his grandmother had told him about the afterlife. As the two strangers drew closer, it was becoming increasingly difficult to follow this train of thought. The haughty-looking man was moving straight towards him, navigating the wrecked shopping strip with alarming ease and wearing an expression that hovered somewhere between apathy and disdain. He might have appeared less frightening had he not been carrying a naked sword, Hiroshi thought. Or perhaps it wasn't the sword that was unsettling, but the use it was being put to; for every time the man passed one of the spirits of the victims, he would thump them wordlessly in the forehead with the hilt, and their eyes would widen briefly in terror before they simply disappeared. Hiroshi had a strong notion that he didn't want to be in the way of this man and his sword with its powers of obliteration, but he was having a difficult time convincing his legs to move him out of harm's way.

"…still don't get why they sent us, though," the redhead was saying. Hiroshi was less concerned about this man: he, too, was carrying a sword, but his trajectory bore rather to the left of his companion's and Hiroshi was sure he would pass him by without seeing him. "Hardly a job for captain-class guys, is it?"

The haughty man swung his hilt into the forehead of a small girl without looking at her. "It is merely a precaution," he said, tone impassive, as the girl faded into thin air. "So many dead spirits in one place tend to attract Hollows. Proper procedure dictates that squads deployed to disaster zones should contain at least one Shinigami of captain class."

The redhead rolled his eyes behind the other man's back. "Ok, sir, but why are we both here?"

"I was given orders to accompany the squad. I brought you because the mission provides a good opportunity for me to observe your leadership skills on the field."

"Right," muttered the redhead, not looking entirely satisfied with this answer. Then he shrugged, and grinned at the haughty man, who still had his back to him. "But you know, Kuchiki-taichou…I think your konso method is, uh, scaring the pluses…"

The man called Kuchiki ignored this, throwing off two rapid blows with his hilt and causing the petrified elderly couple before him to vanish.

His companion persisted. "I mean, it's nicer to stop and talk to them a bit, you know? Let 'em know what you're doing, where you're sending them, that kinda thing."

Kuchiki turned at this, arching a brow. "Why? They'll figure it out on arrival. We're here to work, Renji, not to socialise."

Renji looked both amused and exasperated. "Understood, sir. But is it ok if I reassure them a bit, long as I keep it quick?"

"Do as you please," said Kuchiki indifferently.

He was right in front of Hiroshi now. This was it. Trembling all over, Hiroshi forced himself to look up. Kuchiki's unreadable gaze was fixed on Renji, who had knelt down beside a young woman not far off and was addressing her with words of comfort that Hiroshi couldn't hear. This temporary diversion of Kuchiki's attention allowed Hiroshi to gather up the last shreds of his courage and speak.

"Excuse me," he said, dimly aware that his voice was shaking as badly as his limbs. "What…what's going on? Am I…I mean, what are you about to do to me?"

Cool grey eyes turned to him. Kuchiki blinked, seemingly surprised at being addressed. "You've died," he said bluntly. "I'm sending you on."

Hiroshi fought hard not to whimper in fear. "Sending me…on? I don't-"

The sword hilt rapped him sharply on the brow, and Saito Hiroshi experienced a split second of pure, unadulterated panic before the world disappeared and he crossed over.

Renji leaned back in his chair and rubbed his eyes, fighting back a yawn. The sun had long since set outside his window, and if he'd been working under any normal captain he'd have been well and truly off duty by this hour. But Kuchiki-taichou's personal take on working hours seemed to have little to do with considerations of health or sanity, and the man was still firmly installed in his office attending to his paperwork. Renji was determined not to leave before him, but his resolve was being sorely tested. Didn't Kuchiki-taichou ever need to rest?

It had occurred to Renji more than once that his captain's always-formidable work ethic had been even more apparent than usual over the past couple of weeks. This wouldn't have stood out if the workload had been heavier than usual, but unless Kuchiki-taichou was keeping a large body of extra paperwork secret from his lieutenant (which, to be fair, was possible), then it was about the same as usual – not light, but also not heavy enough to warrant so many extra hours logged in the office.
Renji had a funny feeling that he knew what had prompted this extra show of zeal. And, since it was really his fault to begin with, there was nothing for it but to act the dutiful subordinate and match Kuchiki-taichou's ridiculously extended working hours. After all, it just wasn't polite to leave work before his superior.

There was no ulterior motive. The fact that the rest of the division had already retired, leaving Renji and Kuchiki-taichou alone together, had nothing to do with it. There was no discussion to be had between them that required privacy; nothing that could not just as easily take place in the middle of the day in eye- and ear-shot of the rank and file. At an hour like this there was no real reason for them to interact, which was why Renji was notstraining his ears in the silence of the empty offices for any sounds of movement that might herald his captain's appearance in the open doorway. Nor, for that matter, was he mentally rehearsing the things he might say should his captain happen to approach him that night. He was in the office at that hour because he was a good lieutenant, and that was all.

It was three weeks since they had come back from the World of the Living, having restored Kurosaki Ichigo's powers and disposed of the Fullbringers. Three weeks since he had followed Kuchiki-taichou back to the office, both of them newly healed but still dishevelled and covered in dirt and dust and blood. And although Kuchiki-taichou carried himself with the same regal composure as usual, although his calm expression was firmly in place, the air around him seemed to cracklewith barely-contained reiatsu. There was not, Renji had realised, a trace of anger in his aura. And so he had pushed the boundaries, as he had become more accustomed to doing in recent months.

"You seem worked up, sir," he had said casually. "Good fight, was it?"

Kuchiki-taichou had looked at him, then, and although his expression didn't change, his grey eyes were alight with reckless energy. "It was," he agreed. The faintest trace of a smile curled the corners of his mouth. "I have never fought with such abandon before. It was...exhilarating."

This admission pleased Renji. Not so very long ago, Kuchiki-taichou would not have seen fit to disclose his post-battle sentiments to his lieutenant. Aizen's defection and the subsequent war had wrought changes in both of them, however. Kuchiki-taichou had thawed considerably – he talked more, and listened more, and generally made himself more approachable. Renji had grown stronger and more confident, and had left behind the seething resentment and terror that used to sizzle through his veins whenever Kuchiki-taichou was near. This made it considerably easier to work with the man, and little by little, in defiance of all probability and expectations, the relationship between them had turned into…well, 'friendship' would be pushing it much too far, but there was a kind of respectful camaraderie between them now. Renji's admiration no longer burned him; the heat his captain's gaze stirred in him had taken on a different quality, far less painful, a heat he sought out more and more.

That heat seemed to shimmer in the air between them now, fuelled by the fierce energy of Kuchiki-taichou's reiatsu.

"What was it that happened, sir?" Renji asked. "I thought once that guy cut you he kinda took over your memories, and, well…" He gestured wordlessly at the slash in Kuchiki-taichou's shihakusho and the recently-healed wound beneath it.

"Correct," said Kuchiki-taichou. "He established himself as my mentor in swordsmanship, and inserted himself into Senbonzakura's past to learn my techniques and their counters."

Renji stared. "So how'd you get past him?"

"I improvised."

So that was it. Renji knew how much his captain valued preparation, how devoted he was to achieving mastery of every technique in his arsenal. This must have been the first time his captain had let go and just fought. Renji knew well how exhilarating that experience could be.

He wasn't expecting Kuchiki-taichou to offer any further comment, so the next admission took him by surprise. "For a moment, I wasn't actually sure if I could beat him."

It might have gone unnoticed by anyone else, but Renji worked with Kuchiki-taichou every day, knew all of his mannerisms like the back of his own hand, and there was just the slightest tremble in Kuchiki-taichou's voice as he spoke. Renji's first thought was that Kuchiki-taichou was ashamed, but then he saw it, faint but unmistakeable: the tiniest smirk on his captain's lips.

Holy shit, thought Renji, he's fucking exhilarated.

It struck Renji then that they were standing rather closer together than was strictly necessary. It was as though the wild pulse of his captain's reiatsu was pulling him in, infecting him with the same euphoria shining in those usually blank grey eyes.

It really was intoxicating, that energy. They were closer still, but Renji couldn't remember either of them having moved. Fifty years of watching and waiting, of burning resentment and aching desire, were pounding in his ears, blotting out all rational thought. And so without thinking, without pausing to consider the outcome of his actions, Renji moved in closer until he was almost nose to nose with Kuchiki-taichou.

"I know that feeling, sir," he murmured.

Then their lips touched, and the rest of the world faded into total irrelevance.

Kuchiki-taichou reacted almost immediately, and Renji found himself slammed hard against the office wall, his head spinning and his heart racing as Kuchiki-taichou kissed him as though he wanted to completely devour him. It didn't even cross his mind to struggle for control of the kiss, and he could practically tastethe adrenaline on the other man's tongue, could feel the frantic beating of Kuchiki-taichou's heart as he clung desperately onto the front of his shihakusho and prayed for this never to stop.

His prayers, alas, had gone unheeded. Kuchiki-taichou had pulled away moments later, the exhilaration in his eyes rapidly giving way to something that looked rather like panic.

"Um," he had said after a long and horribly awkward pause.

"Er," Renji had added helpfully.

Then Kuchiki-taichou had departed – bolted, almost – leaving a rumpled, flushed and utterly shell-shocked Renji to peel himself off the wall and make his way back to his quarters for a night of very disorienting dreams.

Three weeks later, Kuchiki-taichou seemed to have himself firmly convinced that the incident had never taken place. And so Renji, too much of a coward to burst his captain's bubble of denial, was whiling away the long evenings in his office trudging through every available scrap of paperwork and emphatically not expecting anything to come of it.

He looked down at the page in front of him. A request for a transfer of sleeping quarters from one of the recent recruits, who apparently wasn't getting along very well with his next-door neighbour in the barracks. God, was he scraping the bottom of the barrel now. Crap like this should have been sent off to one of the lower-ranking administrative officers, but he'd deliberately hung on to a stack of these things, knowing he'd need an excuse to stay in the office once his own paperwork inevitably ran out. Why couldn't the captain just go home already? If he wanted to avoid Renji, he didn't need to hide behind a ridiculously padded-out workload. It would have made so much more sense to stay out of the office as much as possible. Was he trying to prove something?

Renji yawned again. A split second later, he realised he had forgotten to stifle it.

"Retire for the day, Renji." Kuchiki-taichou's voice filtered clearly through the wall dividing their offices.

Damn it.

"It's fine, taichou," he called back, trying to sound as peppy as possible to make up for his show of weakness. "I've still got work to do."

Kuchiki-taichou didn't reply. Renji made a brave attempt at returning his attention to his work. He was so tired that the words were starting to blur together…there was no helping it…if Kuchiki-taichou didn't finish soon, he was going to have to leave anyway…

His head jolted back up as Kuchiki-taichou appeared in front of his desk. How the hell does he move so quietly?

"You have been detained here by pressing business, I see," said the captain, examining the paper between them and raising an eyebrow.. Their sudden proximity set Renji's heart racing in his chest, but Kuchiki-taichou didn't look at him. His eyes stayed fixed on the paper on Renji's desk, as though its contents genuinely interested him.

"Well…" Renji faltered. "That is…it's rude to leave before you, sir." His captain didn't look the least bit tired, he noticed. His shoulders were perfectly straight, his face a mask of cool composure, his eyes alert and unreadable.

Renji remembered how those eyes had looked when that composure faltered; how that gaze when it fell on him had seemed to scorch him with is heat. The air felt thicker than it usually did, and he looked down quickly.

"Ruder still to ignore a direct dismissal, however," said Kuchiki-taichou. His tone wasn't sharp, but nor did it invite dissent. He turned to leave, still without looking at Renji. "Retire for the night. There's no need for you to be here."

"Thank you, sir," Renji responded mechanically. Inwardly he cursed his own passivity, his inability either to forget what had happened or to insist upon bringing it up. What would happen if he just reached out and caught Kuchiki-taichou's sleeve, forced Kuchiki-taichou to look him in the eye, and demanded to know what Kuchiki-taichou wanted from him?

I'd be lucky to live.

And then Kuchiki-taichou was gone, and there was nothing for Renji to do but put away his things and close up his office and head back to his room in the barracks for the night.

And if the faintest sigh had happened to escape Kuchiki-taichou's lips as he returned to his desk and his half-completed budget report that wasn't due for several weeks, then Renji wasn't around to hear it.

"Yo, Kuchiki."

Byakuya closed his eyes, trying to suppress the wave of reflexive irritation that coursed through him at the sound of that voice. When that proved ineffective, he opened them again and turned reluctantly to face his assailant.

"Zaraki. How unlike you to arrive early for a meeting."

Zaraki Kenpachi was lounging against the wall of the meeting room in the First Division compound, as unsightly as ever with his torn shihakusho and a smear of dirt on his jaw. "Training finished early," he explained, apparently choosing to interpret Byakuya's jab as an expression of sincere interest. "All my blokes wimped out before I even got warmed up, so I figured I'd just kill time 'round here. Hey, wanna go a quick round before the geezer gets here? Reckon there's enough time to kick your ass…"

"I decline."

Zaraki heaved a bored sigh. "Knew you'd say that."

Silence reigned for a few precious moments. Byakuya resisted the urge to mimic Zaraki's comfortable posture against the wall. He didn't intend to let it show, but he was tired. Sleep had been eluding him lately, and his methods of whiling away the moonlit hours – reading, mostly, and strolling through his gardens, and practicing calligraphy – did wonders for the soul but frustratingly little for the weary body. To be honest he found it a little disconcerting, the extent to which his recent bout of insomnia was wearing on him. He'd never been much of a sleeper: five or six hours usually sufficed, and at a pinch he could function perfectly well on much less. The couple of hours rest he was able to snatch before dawn weren't ideal, but they shouldn't be leaving his body feeling so heavy, his mind so hazy.

His train of thought was interrupted by the unnecessarily flamboyant arrival of Kyouraku Shunsui, who somehow contrived to make his bright kimono swirl dramatically about him as he appeared in the doorway. "Good morning, gentlemen," he greeted his colleagues. "I hope I find you well?"

"Quite," said Byakuya, trying not to look at the fluttering kimono, which inexplicably made him feel rather dizzy this morning. "And yourself?"

Kyouraku heaved a dramatic sigh. "Alas, far from it," he said, taking his place next to Byakuya. "My Nanao-chan gave me the most fierce telling-off this morning, and I begin to fear that she will never be persuaded to love me."

Byakuya deemed this line of conversation unworthy of his engagement, and wondered if ignoring it would discourage the other man or simply provide him with the opportunity to enlarge upon his woes. Zaraki had his own ideas, however.

"What did you do?" asked the Eleventh Division captain, looking mildly curious – although not curious enough to stand up straight, apparently.

"I failed to rise at what she deemed an appropriate hour," said Kyouraku, expression comically morose. "She has accused me of laziness and irresponsibility."

Zaraki snorted. "Gee, that's a new one."

Byakuya tuned out the ensuing inane banter, his mind wandering instead to the subject to be broached in today's meeting. He was not looking forward to it. One of his soldiers was soon to face trial for misconduct during last week's mission cleaning up after an earthquake in the World of the Living. It seemed that the boy - he was barely old enough to be called a man - had taken it upon himself to hurry along the fate of a soul who was still alive. The punishment for such actions could be severe - the law strictly prohibited Shinigami from intervening in the natural cycle of life and death of humans.

Byakuya had interviewed him briefly, while he was detained in the Sixth Division's holding cells. The boy had made no attempt to conceal his crime, and had appeared frightened but unrepentant as he explained that the human in question had sustained horrendous injuries and looked to be beyond recovery when he found her.

"She could see me, taichou," he had said, his voice trembling slightly. "She could see me, and she was begging me to help her die, she was in so much pain."

Byakuya felt some sympathy for the boy. One of the more difficult tasks of the Shinigami was to learn to witness human suffering impassively, to overcome the urge to take pity on living souls and interfere with the hands that fate had dealt them. Byakuya himself didn't find it easy to suppress the instinctive horror of seeing such agony, or the desire to step in and alleviate that agony where he could - empathy was a natural trait, and all his years as a Shinigami and all the attending scenes of disaster he had witnessed had not made him immune to it. He could understand, then, that for a mere youth, fresh out of the Academy with no real experience on the job, the mission must have been confronting.

However, the law existed for a reason. Shinigami were not gods. It was not their place to decide the lifespan of humans. Theirs was to guide dead souls into the afterlife, to purify Hollows, to maintain the balance between the two worlds. There could be no exceptions made - the fate of the living was outside their jurisdiction, and those who sought to subjugate human fate had to be punished, regardless of the purity of their intentions.

Furthermore, the incident did not exactly reflect well on Byakuya. As the commanding officer on the scene, he should have ensured there was sufficient supervision to prevent such a transgression from occurring. He should have kept a closer eye on the more inexperienced squad members who had yet to prove their ability to handle their responsibility on the field.

His excuse - that the widespread nature of the disaster, the chaos and the sheer scope of the operation made it implausible for him to monitor the actions of every single squad member - would be sufficient for the captain-commander, but it didn't satisfy Byakuya. There were, he reminded himself, two people present that day who were capable of commanding and supervising the troops. He had taken his lieutenant with him, after all, and he should have divided the squad between the two of them, and each kept a closer watch over a smaller group. There was no guarantee that such a measure would have prevented what had happened, but it would certainly have been more effective than the arrangement he had preferred.

He was thoroughly irritated with himself.

Routine was not the same as safe - he knew that perfectly well. And yet he had persuaded himself that there was no need for stringency on such a routine mission, and had foregone sensible precautions in favour of personal indulgence. For he had enjoyed the company of his lieutenant, enjoyed the casual banter as they trudged their way through an otherwise dreary task. He had been very deliberately avoiding unnecessary interaction with Renji since that incident, had not trusted himself to be alone with him for any length of time. But out in the field, surrounded by his troops and with a shared task in front of them, Renji's presence had not seemed a threat. He had been able to relax and simply enjoy the time spent with the other man. His selfishness had promptly and predictably led him into trouble, as it always did.

If only he didn't have such a foolish heart.

Well, he would make his excuse and his apology anyway, and then he would petition on behalf of his convicted subordinate for a reasonable sentence - for a firm punishment, but not an overly severe one. And then he would spend the rest of the day working hard enough to blot out any conflict in his heart, any memories he shouldn't linger on or desires he shouldn't cherish. And then perhaps - perhaps - he might actually get some sleep tonight.

Yamamoto-soutaichou cleared his throat, and Byakuya was jolted out of his thoughts to realise that the hall had filled and the meeting was about to begin. He really was tired; lack of sleep had never made him so unobservant before. Biting back an irritable sigh, he steeled himself to make his report.

Night fell over Seireitei without any particular fanfare. An intrepid but somewhat foolish wood-mouse, shunning the furtive habits of its forefathers, ventured out of the shelter of the trees to the grassy plains beyond in search of adventure; a young scops owl, stunned by its own good fortune, enjoyed a far heartier dinner than its usual fare of crickets and small lizards. Several upperclassmen at the Shin'ou Academy snuck out of their dormitories to share a bottle of contraband liquor behind the Zanjutsu training hall.

In his small but comfortable sleeping quarters at the Sixth Division barracks, Abarai Renji slept fitfully. He dreamt of heat and frustration; of pale skin and inky black hair; of steely grey eyes and a slender, well-muscled body pressed against him.

In a large, sparsely furnished room overlooking a gently bubbling stream and a tidy moonlit garden, Kuchiki Byakuya sat sleepless at his low desk and tried, with limited success, to train his weary mind on the joys of classical literature.

And in a cold, dark holding cell in the Sixth Division compound, Itou Susumu, recent graduate of the Shin'ou Academy and unseated officer of the Gotei 13, stared miserably up at the shadowy ceiling, the desperate pleas of a dying stranger echoing in his mind.