A/N: Okay, A... sink or swim. ^_^' Your reviews make me giddy with joy, and I feel truly honored by your words: they also make me incredibly nervous. x') You like my characterization of Mephisto, and if you still like it after this... then I will breath a sigh of relief. I can only hope I've done this the right way. I hope I can swim.

I do not own or profit from any of what Kazue Kato has created.

Daylight was dimming, but Mephisto was still in his office: Shiro could feel it. Feel it in every bristling hair on his body.

"You are not worming yourself out of this." His steps echoed heavily in the empty corridor. "I don't fucking care if I'm one human up against the King of Time: you are not getting away with something like this." The echo of war drums.

"Normally, people knock." The demon didn't even look up from his chessboard.

"Monkeys aren't people. I figured you wouldn't be very busy this time of day anyway." He sauntered over to the heavy wooden desk with his hands in his pockets – the lighter was already gone. "I met Kasumi-chan today: she told me to pass greetings to you."

"Then give her my greetings in return~ Charming girl, that; pity she has those distasteful tattoos."

Mephisto still hadn't even looked at him. Could it really be so concentration demanding to make the first move against yourself, or was he ignoring him deliberately?

"She should've been here yesterday, but she got held up on her way down from the Futotsuki's", said Shiro casually, and seated himself on the edge of the desk: if that didn't get Mephisto's attention, then-

*poof*

An armchair from the striped furniture set around the table appeared in front of the desk, demanding to be used.

"As I was saying, she got held up", he continued, rising from the desk but ignoring the chair. "There had been some kind of accident while we were away at the meeting. Earthquake, I think. She stayed and prayed for the victims – ninety dead, or around those figures."

"What a lovely date you must have had, with such topics", he smiled, still pondering where to place his first white piece.

"At least I can date her, warding tattoos and all. But we did get into discussing earthquakes." Shiro intently studied the thin lips, the hair curl, the ears, the eyes lowered at the board; anything that could betray a reaction. "The one that struck there – St. Nicholas, I think the place was called – wasn't very strong, but it still shook the place to pieces, and left no survivors. None, out of the ninety-two that lived there." No reaction. Idly turning his chess piece between his fingers, as if he wasn't even listening. "I just thought I should ask, since you've got a brother that's King of Earth", he ventured, connecting the dots Mephisto pretended to be blissfully unaware of. "If a weak earthquake occurs within a very small perimeter, can it still be that destructive?"

A very, very small perimeter, with St. Nicholas in the epicentre.

"My brother is the expert, admittedly, but I suppose it could", was his reply. "Small quakes are very common, especially here in Japan. They seldom cause any damage – unless they hit gas pipes in poor condition, as I believe was the case with the one you speak of."

"You seem to know quite a bit about it." Doubt evaporated slowly off his heating temper as the perfect façade remained perfect. "Does that name ring a bell with you? St. Nicholas?"

"Never met him in person", Mephisto confessed. "Greece was a lovely place to live, in ancient times, but Christianity always did tend to spoil one's fun. I think we missed each other by at least eight centuries."

"I meant the place: the orphanage St. Nicholas." Shiro's voice took on an edge of crude, grating steel. "The one that was completely bulldozed in a very unnatural earthquake while you were getting yourself a perfect alibi at the Futotsuki meeting."

"Such harsh tones~" At least he looked at him, even if it was a blithe look of I-have-no-idea-why-you're-so-upset that tempted Shiro to smash his teeth in. "I'm King of Time, you know; I believe the one you should be directing your glares at is the King of Earth."

A silver tongue to veil any lie in the light of truth; a sweet voice to make bitter poison appear like pristine ambrosia. The most devious weapon in a demon's arsenal.

Shiro stared the black-suited, smooth-talking snake down over the desk. He could send an entire clan of demons to their death, fine: demon society, demon rules. But an orphanage of human children…

There are some things you just don't do.

"So it's complete coincidence that that was the orphanage Agari-chan was from?" he said in low, calm tones that answered the question on their own.

The mask didn't slip, no. Mephisto could have been confronted with mountains of conclusive evidence and still worn that face of idle innocence. No: he took the mask off, and revealed the calculating amusement underneath.

Amusement.

Not guilt or regret or pity: amusement.

"Katsuda Agari, Komui Natsuya, Ayabito Susumu, Inoue Katsu, Sato Michio, Kobayashi Shizue." His lilting voice trickled over the names like a creek over rocks. "All orphans, adopted from St. Nicholas: all trained there to be fully capable exorcists before they ever set foot in my academy."

Trained...?

Orphans... trained...?

The words seeped into him like winter's breath through an old door. Trained orphans. An assassination squad of sleeper agents. Child soldiers for a suicide mission; children that had lost everything already, except their lives. What despicable mind would-

"St. Nicholas was a Catholic orphanage…" Pieces fit together; thoughts raced ahead, kicked in doors and surveyed possibilities. "It couldn't be, the Vatican…?" That wasn't the real question, of course. "Why is he telling me this?" Mephisto didn't play with open cards, not even with the promise of trust in mind. "He trusts you alright", a cynical part of his mind huffed. "He trusts you to be smart enough to figure out his game through tracing strings and guessing riddles. Teaching you to think like a demon."

Did he even want to-?

Oh, he wanted to. Danger had only ever spurred his curiosity on. There is a twisted fascination with mystery and malice in the human heart; and his heart…

Am I a master smith? Am I shaping you this very moment, for some distant purpose in a future only I can see?

…was marked by the devil in the high-backed chair.

"My Roman bed-mate may be a cold lover, but not so cold as to hide a dagger beneath her pillow", Mephisto said with an air of cool, well-measured amusement. "St. Nicholas specifically accepted children orphaned in demon attacks: aside the usual education, said orphans were also given rigorous training in exorcism and military combat. This somewhat unusual childcare was privately funded, by an anonymous founder who has turned out to be a Cardinal Basilio Tanzi." The chess piece rolled back and forth between his fingers, back and forth as he surveyed his game board with lazy, heavy-lidded eyes. "A Cardinal who, the day after the incident in Deep Keep, left his residence to live at an unknown location. The only contact the rest of the world has had with him since is sporadic messages by telex."

Shiro didn't play chess, but he knew enough of it to catch the irony: the piece between Mephisto's fingers was a bishop.

"You look awfully calm, given the circumstances. You don't think he's told anyone by now?"

"Omniscient am I not, but much is known to me: had there been whispers of my name in the corridors of Headquarters I would have known. Tanzi is a fool, not an idiot." He snapped his fingers and summoned a paper to his desk. "Chess is won by stratagem, not by numbers: he sent no army to contest me, but six assassins carefully cloaked in inconspicuousness."

He slid the paper over to Shiro, whose first thought was that the demon must've been in a hurry when he wrote. After a closer look, he discarded it altogether as something written by Mephisto. The crinkly paper was covered in crude, impatient handwriting jotted down with a plain ballpoint pen – which meant those splotches weren't Mephisto's deep red ink…

"Katsu Inoue came here 1965, and made a very good impression on the teachers: good enough to be admitted apprenticeship as guard in Deep Keep."

Katsu Inoue: infiltration, armed support, recconnassanse

"Komui Natsuya, Kobayashi Shizue and Sato Michio enrolled three years later; Katsu was in position by then, and had confirmed that the dimensional pocket could not be accessed without disabling the wards that sealed it."

Komui Natsuya: marksman, armed support, reconaissanse

Kobayashi Shizue: low-level psychic, ability to dowse for energy signatures

Sato Michio: swordsman, armed support, reconassanse

"Das Labyrinth des Limbus must've proven quite the obstacle for Kobayashi-chan: it wasn't until the last two cogs in the machinery were accepted into the Academy this previous year that they could reach the wards in there. Katsuda Agari bought her basic materials from True Cross Town and the exorcist supply shop, and devised an arsenal of surprisingly sophisticated timed explosive devices to wipe out the entire seal at once."

Katsuda Agari: explosives technician, armed support

"Ayabito Susumu was quite the interesting case", Mephisto mused on, resting his cheek in his hand with the elbow supported on the desk. "A genius of numbers that not only fortified the seal to isolate my heart, but drew up formulas for navigating inside my labyrinth."

Ayabito Susumu: mathematician, specialised in surjective homomom homephism HOMEOMORPHISM

And, tilting on its own down in one corner, smudged when the paper had been carelessly shoved into a pocket: I can't spell recconnassiense, Aniue

"He even learnt the chant from the Essene scrolls by heart." Mephisto turned the game piece over in his hand slowly, thoughtfully; and made Shiro's intestines tie themselves in knots. "I located the demon who told the Cardinal what those scrolls really contained, and she gave me the same name: Tanzi." The white bishop resumed its place on the board with a soft, clean click.

"And you can't find him…" Shiro murmured, eyes lingering on the bishop hiding behind its row of loyal pawns. The last man on earth who knew Mephisto's true name. One man that could ruin everything he had worked for during one and a half century.

"Tanzi spent near thirty years preparing for his move, and spent just as long preparing his retreat if it failed: hiding from me is very difficult, but he succeeds. He succeeds, because he knows who I am." The glimmer in the eyes was the same, and the sneer that danced on his lips was the same, but that was Samael: Shiro knew, because he noticed he had stopped breathing. "And he knows how eager I am to meet him. He isn't coming out of his shelter for as long as he lives, nor is there anyone outside it who could help him if he revealed what he knows. He hopes", there was a tone hissing around that word that sent chills down Shiro's spine, "that if he buries himself alive, silent and compliant, I won't see any point in digging him out." The demon's presence tensed, curled: a predator ready to leap. "It will be an arduous undertaking, certainly, but I do appreciate a challenge: it's very rude, if nothing else, to resign mid-game."

"He hides it well…" But an imprinted heart could tell that Mephisto was absolutely, hellishly furious.

"Tanzi may have surrounded himself with every imaginable defence against demons, but I will make him finish the game he started."

…and Shiro understood why Mephisto was sharing this information with him.

"I'm not doing it", he said coldly. "Every imaginable defence against demons, but none against humans; is that it?" He could see where this was going, and he would dig his heels into the dirt before Mephisto's smooth-talking got a syllable further. "I'm not becoming your private hitman. If you want the Cardinal dead, you're gonna have to do it yourself."

"Dead?" He looked genuinely surprised that anybody would dream of associating such a word with his pristine white appearance: which at the moment was switched for pitch black. "Shiro, Shiro, who ever said anything of killing? 'To subdue the enemy without fighting is the acme of skill.'"

"And where do ninety-two orphans fit into that quote?" Cold heart, cold mind, cold voice: he didn't sound like a nineteen year old, not even in his own ears.

"In chess there is always sacrifices." Mephisto's voice was light and carefree, but his eyes were sharp with focus. "Tanzi was well aware of that when he sent his assassins into the fray."

Shiro felt as though his windpipe had been blocked with a fistful of burning coal.

"You inhuman fucking...!" In chess there were sacrifices, yes: but reality wasn't a bloody game. Real lives weren't game pieces that-

To a demon they are.

Time stopped, and his breath ached past the tight knot in his throat. He met the green gaze of the demon posing as a man before him: there was no guilt in that face, because demons feel no such thing. No pity, no shame, no concept of human right and wrong.

"To a demon we're just puppets and playthings."

Time regained momentum, and Shiro shuddered involuntarily. His gaze fell away: fell to the chessboard, where the neatly lined-up pawns formed walls of faceless cannon fodder: genderless, featureless, unimportant meat shields whose sole purpose was to fight and die at the hands of the kings that moved them.

…fight and die… in the gloved hands of the king that moved him…

"Chess is a game of war", Mephisto spoke softly, seeing where Shiro's attention lay. "As long as war is waged, lives are lost: until one king surrenders, no piece on the board is safe." Green eyes sought his, and gloved fingers braided together to form a podium for the words that left the demon's mouth. "Some would say it's testimony of a player's skill to capture the king with subtly layered traps: the true master of the game, however, needs no traps or decoys. The true master is the one that can pull checkmate with the naked elegance of a single move." Mephisto rested his eyes on him expectantly, waiting… "The acme of skill." …waiting for him to make his move.

Shiro's breath fell from his lips, and the ground from underneath his feet.

Skilled he was. And not only at war games.

Checkmate in one move. Checkmate with only one piece: one piece that could ensure no others had to be sacrificed again. One piece that was prepared to do anything to wash its black conscience a little whiter.

Shiro clenched his teeth around the haunting echo of that single gunshot in Deep Keep.

One bullet

One chess piece

One choice

"You devil…"

Know your enemy, and you can predict his actions

"No one knows the human heart like a demon."

Predict your enemy's actions, and you can lead him wherever you like

"No one knows mine like you do."

To the true master, the enemy is but another game piece to be played

"…I never played by the rules."

"Let's be clear about one thing, Samael." Indeed, names are powerful things. Now that he paid attention, Shiro could see it affecting him, too. Mephisto didn't wince, as other demons would have, but he wasn't used to hearing that name any more than they were. "I don't give a damn about your schemes and vendettas. You'll do as you please – as you always do – but I'm not your game piece. I will not be moved by you, or anyone else. This pawn", he picked a matte black piece off the board, "is not part of the game." Without breaking eye contact, he grimly put the pawn down on the desk with a hard click.

There. A challenge. A declaration of war, against war, for continued war: it crackled in the air between them; demon and human, king and pawn. Let's see how he dealt with-

"Oooh, I like that look!" Liked? Mephisto seemed about to fly out of his chair with excitement, white-clad hands flat on his desk and eyes-

-Shiro had never seen his eyes opened up like this, had never seen them burn like this, never-

"Such determination! Such cold flame in those eyes! No use arguing against a man with a look like that upon his features: I bow to your decision." …What? "Your move may be rather, so to speak, unorthodox", the green eyes darted down to the pawn for a moment, and returned with only glowing coals remaining of the fire, "but the right to move is yours alone."

The element of surprise may be a fundamental part of war strategy, but no one could work it like Mephisto. He simply dropped the matter? Just like that?

Shiro's brow furrowed.

"You're not…? Not gonna go after the Cardinal, then?"

"There are countless ways to capture a king", he said flippantly, and produced a packet of chocolate-flavoured pocky out of the air. "'Water shapes its course according to the nature of the ground over which it flows', and so the strategy changes to suit the game." The pocky stick snapped between the sharp teeth in his smile. "I can play one piece short."

And win regardless, the unfinished sentence continued silently. Though there might be a few pieces captured and sacrificed before I do.

"…I'll never figure out how you do it. How you switch from creepy-as-fuck back to normal like this." Shiro snapped his fingers. "If this is your normal", he added, studying the human face that housed no human mind.

No, completely unfazed. Calm and untroubled and mildly surprised. And amused. Always amused; no matter how dark or hostile atmospheres were, no matter if ninety died or nine hundred, there always seemed to be a smile hiding in the corners of that mouth. Normal wasn't a word that applied to Mephisto in any form.

"Stevenson made a rather good study of that." The demon underlined the statement with a tap of the half pocky stick. "Jekyll and Hyde are one and the same, separated only by human conscience; which I am, quite logically, not afflicted with. That's one of the great ironies my employers in Headquarters have always failed to see the humour in", he continued, amusement bringing his odd cadence to bounce to the idle conducting of the pocky. "While humans live a lie, demons are always honest about what they are." And with a conscienceless smile and a wink, he ate the remainder of the stick.

The ground... was back under his feet. More solid than ever before. More hard and uncompromising than ever before.

There was no demon Mephisto or person Mephisto: there was only Mephisto. The King of Time. A demon without conscience. So gruesomely honest that the human mind couldn't comprehend it.

"…I'm gonna have to think about that for a while", Shiro murmured, and put a cigarette between his teeth. "And I'm gonna need my lighter."

"You come to yell at me, and then immediately leave when you're done? Tsk tsk, such manners."

Manners...?

Shiro had completely forgotten that there was such a word: completely forgotten that even if he played human lives like puppets, Mephisto would always crinkle his nose at sloppy ties and saucers that didn't match the cups. Jekyll and Hyde, all at once, always.

"It's your own fault, in every way", Shiro pointed out over his shoulder, headed for the door and the long, long walk this would take. "I'll be having exams every single day for two weeks, Sir I-okay-all-schedule-drafts-while-I'm-watching-anime. And I need grades to justify that scholarship you got me."

"Such a model student." Mephisto snapped his fingers, and the lighter returned to its usual pocket. "You will make a fine exorcist, I'm sure."

A/N:

I don't use the name of any real Cardinal, since I'm not that keen on being accused of slander. I will give Tanzi the title of a real Cardinal, however; he can't very well go without one.

Telex is a network for sending text messages, like a very, very old-fashioned fax interbred with landline phone.

There were few quotes on war strategy from Sun Tzu's The Art of War, and a few tweaked additions of my own to fit the chess metaphor.

Omniscient am I not, but much is known to me Quoting Goethe here, and choosing to go with his Mephisto before Kato's.

In the manga, Mephisto says "I know everything". Without hearing him say it, I have a hard time knowing if he means "I know everything (that has happened with Godain and your friends)" or "I know everything (literally everything)". He could probably mean the latter, given his convenient method of spying on anyone, but that would make him a tad OP imo. Omnipotence is no fun. ^_^' A character that knows everything and can do (almost) anything kills a story.

So I couldn't go with canon all the way, which I apologise for. x/ In my defence, he's just as curious as anyone else to "find out what lies ahead", as he puts it: so he might not know literally everything.

The Essene were the Christian sect that preserved and hid what we know as the Dead Sea Scrolls (that I used in arc 1). There's a fair amount of conspiracy theories around those, for those interested in such things.

Surjective homeomorphism I am in no way a mathematical-minded person. Merely wrapping my head around the terms I had to investigate to piece together this (admittedly self-contradictive) field of science made me haemorrhage from my auditory canals. I may have gotten things entirely wrong, too. x')

So, topology is a field of geometry in mathematics that concerns deformation of objects in space: things, plain and simple, and how they can be stretched and bent in the dimensions they exist in.

Homeomorphism, if I have understood it correctly, is deformation from one shape to another. It's based on a set of continuous functions coupled with inverse functions, which in simple English means that object A will deform into object B, and then back into object A endlessly: the deformation only moves between object A and object B, nothing else.

That's where I added surjection. Surjection means that function A, B and C all can yield Q, and reversely Q can give you either A, B or C depending on which part of the graph (or in topology: which part of the object) you're looking at.

To sum it up, surjection is incompatible with the concept of homeomorphism; but if it theoretically were possible to use the two in junction, you would get a deformation of an object that is both erratic (turns into A, B, or C) and inconsistent between different parts of the object (one part may go from Q to C, while another decides to go from Q to A). You would get a house where your bathroom door could lead both to the bathroom and to the living room, closet, or pantry (or some stage between those) depending on the deformation of that specific part of space in the specific moment you open the door. You would get das Labyrinth des Limbus.