This all started out back when the early info about Guilty Gear 2: Overture started showing up on the web - with all those tantalising pictures of that mysterious new Sin character who travels around with Sol and bears a startling resemblance to Ky - and people started coming up with some fun little crack theories about his origins. And look, really, if all the new info that's come out since has only added new evidence to the point that theory actually started sounding plausible, and if certain people kept egging me on to take the idea to its logical conclusion, it's not really all my fault, is it?

A quick bit of intro
In the interests of full disclosure, here's what we actually officially know so far about Sin. He's been travelling the world with Sol for the last few years to polish his bounty hunting skills, though since only four years are supposed to have passed since GGXX, he can't have been around for all that long. He calls Sol 'oyaji', which means 'Old Man' in the same kind of sense that you'd refer to your father as your old man - and Sol, by all accounts, seems pretty content to have him around. According to Sin's bio, his hobbies are coming up with original adjectives (no, really!) and overcoming his weaknesses, and he hates being treated like a kid. He seems to have this little obsession going with beating Sol, quotes random factoids about obscure Indian gods of weather and war before battle, and generally comes across as a brash, naïve, optimistic kind of guy.

Appearance-wise, he's blond with eyes that alternate between blue and green based on which piece of official art we look at, has a fondness for blue and white clothing with cross-designs, and wears a metallic-looking eye patch over his left eye and a crucifix around his neck which he touches briefly in his battle opening. In addition to his oversized denim flag, he fights using lightning magic and all the exact same Servant units that support Ky in battle. His tension move is abbreviated on the official site as 'R.T.L.', and something about the description that goes with it sounds awfully familiar. None of the official info has actually gone so far as to say there's a giant connection between him and Ky, but when it comes down to it, they don't really need to, do they?

A couple of lines at the end of this fic were (loosely) borrowed from plot-related screenshots. The rest is merely the product of my own twisted imagination.


The lower basement labs of what had until recently been the Post War Administration Bureau had been full of unpleasant surprises, which only got worse and more bizarre the lower they went. By the very bottom level, Ky was thoroughly on edge, so when he heard something say, "Ba-boo?" behind him and his first instinctive response was to whirl around and point his sword at it, it was really quite well justified.

The baby gurgled at the thing being pointed at him in a clueless sort of way. It didn't spontaneously transform into a giant, fanged monstrosity with extra heads. After a further thirty seconds of the baby not transforming into a giant, fanged monstrosity with extra heads, Ky lowered his sword again. The baby seemed mildly disappointed by this.

"To think they were even experimenting on innocent children in this place," Ky said aloud, quite disgusted, and knelt down with the trepidation of a man who only vaguely knew what one was supposed to do with babies (and really, would have been rather more at home dealing with a fanged monstrosity, all things considered).

Sol kicked a computer and was rewarded by a screen waking up to show him a readout on something called "The S.I.N. Project" in the unnaturally large and well-illustrated font that mad scientists always seemed to have to resort to in order to explain their side projects to their superiors. He was reading through it for the second time, and maintaining control of his eyebrows and jaw only by serious effort, when Ky called urgently to him, "Sol! This child – there's a Gear mark over his right eye!"

"Be quiet," Sol growled.

"He's an infant Gear, Sol! Surely you can't have found anything more important than that! If the Bureau were experimenting with Gear cells on..."

"Ky. Shut up."

Ky opened his mouth and then shut it again. That was hardly fair. Sol never used his name for anything so trivial – not even the slightly awkward truce lately declared between them for the occasion had changed that aspect of their relationship.

"Need you to read something," said Sol, frowning as he beckoned Ky over.

It had better be a very good reason, Ky thought as he walked over to the colourful screen.

Not having Sol's control, Ky's own jaw dropped most of the way to the floor before he'd finished reading through the first time.


"So that," said Ky, much later, out in the sunshine again and finally starting to come to terms with the implications of it all, "that did mean that he's – something like… our…"

"Kid?" supplied Sol. The kid in question was drooling happily on his jacket. "Yeah. Damn." He needed a cigarette, but that would only lead to Ky snapping at him about smoking near the baby, and this was surreal enough already.

Ky had to sit down. Again.

"Of all people, why on earth would they have chosen the two of us as genetic donors for an experiment like this?"

"Yeah, why would they bother making a Gear-you when all those robo-yous were working out so well for them," said Sol, which did rather put it all in perspective.

"I never even imagined having a child," admitted Ky, with feeling.

"Hell of an unexpected surprise," Sol agreed. Ky coloured slightly.

"Really, you're making it sound like one of us got… got knocked up unexpectedly or something."

Well, certainly not for lack of trying, hm? supplied a voice in his head, sounding uncomfortably like several of the most puritanical ministers he'd ever had the misfortune of knowing. They'd probably all have found this very fitting punishment, though Ky himself was certain he'd never heard of any traditional punishment for the sins of sodomy that included something like this.

"Hah," Sol muttered, providing a much needed interruption to his thoughts. "Least that woulda given us some warning."

Ky let out a defeated sigh. "What are we going to do with him? He's half Gear! We can't just give him to anyone to take care of!"

There was a meaningful pause.

"It's going to have to be me, isn't it?" said Ky.

"You want me lugging him around the planet with me?"

"I know, I know," said Ky, rubbing his forehead. "But really, the mere thought of having a child to take care of!" he went on. "And not just because… well, how would I ever have had time for it?

"Although," he concluded, looking properly at the infant for the first time since they'd gotten outside, "I suppose people who do want children are expected to find the time for it."

There was another pause.

"Do you think he looks a bit like me?" Ky wondered.

Sol politely declined to comment.


There are a number of very good reasons why workaholics tend not to have children, and the absence of much of a social life in which to meet other people with whom to produce those children is only one of them. Ordinarily, there should have been someone to recognise that Captain Kiske taking time off voluntarily might well be the first sign of the apocalypse. Fortunately, the massive departmental shake up which resulted once the corruption of the PWAB had been brought to light actually worked in Ky's favour, because his involvement gave him a very convincing excuse to declare himself much overdue for a little time off. His few remaining superiors were only too glad to grant it – keeping him out of the spotlight for a bit was likely to be the only chance they had of preventing him from yet again becoming the sole public hero in the whole fiasco. The more of the clean-up that followed that could be done by anyone other than one Ky Kiske, the better.

Sin himself produced his own special problems. There was no way he could be checked into a regular day care centre without raising all sorts of questions about that birthmark over his eye, so Ky had to go through other avenues. By the time Sin was a year old, he owed the Jellyfish pirates a truly ungodly number of babysitting-related favours. However, Ky remained cautious about just how much detail regarding Sin's precise unlikely genetic makeup he revealed, even to them. It was easier just to say, "He's a half-Gear we found in a PWAB laboratory," and leave the specifics aside. The idea that he'd personally take in a baby under those circumstances wasn't all that implausible, was it?

"Hm," Johnny drawled in response, peering into the crib. "Doesn't he look a bit like you?"

"R…really?" Ky stuttered back, trying and failing not to be too obviously pleased by it.

At least these weren't favours he was going to be greatly begrudged. As far as Dizzy was concerned, having a real baby half-Gear-just-like-her to take care of three times a week was like getting twenty years of Christmases all at once.


Ky's initial concerns that Sin was set to grow up barely able to recognise his other 'parent' were very quickly assuaged when Sin took to greeting Sol on his infrequent visits by latching on to his leg before he'd gotten two paces in through the door.

"When did he learn to walk?" Sol asked suspiciously on the first such occasion.

"A week ago," Ky replied. "And I haven't even had him here two months! I had no idea half-Gears grew this fast."

"Haven't you ever asked Dizzy how old she is?"

"It didn't seem polite," Ky protested.

"She isn't even four yet."

A swift burst of mental calculations later, it was still all Ky could think to say, "My goodness."

"Pa!" said Sin happily, face buried in the fabric of Sol's pants.

"How do you make him let go?" Sol asked, returning to more immediate concerns.

Sin agreed to allow himself to be prised off Sol's leg on the condition he be allowed to sit on his lap instead, where he promptly fell so deeply asleep that neither of them had the heart to wake him up again for a good while after.


Everything changed the following year when all the Iluria business went through, and suddenly, having a child running around who aged at the rate of something equivalent to a year every few months, and who had the occasional habit of referring to Ky in ways usually more suited to one's female parent became a bit politically awkward.

"I don't expect you to take him all the time," Ky explained to Sol, "I just need him out of direct sight now and then."

"So it's my turn to do my share of the parenting, huh?" said Sol. "Aren't you scared of all the bad habits he's going to learn hanging around with me?"

"Terrified," said Ky. "But it's that or give the May Ship its own dock at the castle, and they've got him halfway to believing he's a pirate already."

"So? They stopped him taking off his eye-patch, didn't they?" said Sol.

"They also have him halfway to believing he's a girl."

"…what?"

"Everyone else on board under the age of twenty is."

"Kids." Sol grumbled.

Kingship did have its advantages though. It might have made it hard to keep Sin out of the public spotlight, but it did also give Ky the luxury of being able to respond to the occasional innocent question from less important castle staff and visitors about the identity of the boy with the answer, "That Is Sin." in a tone imperious enough to make the full stop at the end of the sentence echo around the room like a ricocheting bullet, and guarantee no-one present dared raise their heads long enough to ask anything more.


Most people would probably think that a royal flag twirling demonstration would be a fairly safe thing to show an impressionable young well-he-looks-about-seven-now-to-me-year old. Most people would have thought a miniature flag would be a safe sort of present for growing boy ('miniature' meaning 'only slightly taller than he was', but Ky had had a very real certainty to his voice when he'd said, 'he'll grow into it'). But what most people would be forgetting was that the boy in question was a half-Gear who was currently growing and learning at the rate of a snowball accelerating downhill.

Sin thought the flag was the best present ever, which only made the situation all the more awkward. Ky really didn't want to take it off him – he thought it a very good thing to encourage a bit of youthful patriotism (to say nothing of the tantrum Sin would have thrown had anyone tried to separate him from it now). However, the way Sin kept waving the thing around was becoming a bit of a worry, particularly since his attempts at mimicking the flag twirlers usually ended only when he'd whacked himself in the face.

"It doesn't seem to put him off for long, no matter how hard he hits himself," Ky told Sol on his next visit, having already gone through a couple of weeks of exasperation on the subject. "I've had to stuff padding around both ends just to stop him doing himself an injury."

Sol watched Sin waving his flag around with the expression of a man vaguely wondering whether this behaviour could be blamed on the genetic contribution of the other parent. "Don't you have people to do that stuff for you now?"

"Sol, the day you catch me hiring a royal padding stuffer is the day I want you to personally storm this country and put me out of my misery."

"Yeah, whatever," said Sol. "C'mon kid, let's…"

All three of them winced as Sin whacked himself in the back of the kneecaps yet again.

"He's bound to grow out of it before long," said Ky hopefully.

"Bound to," Sol agreed.


Sin did not grow out of it in the first couple of weeks of that particular trip with Sol, though his wild swinging did improve enough for him to graduate from hitting himself with it – on to him hitting everyone else in the vicinity.

"Knock it the fuck off!" Sol snapped at him, after being hit in the same place on the lower leg for the third time that morning.

"The what?" said Sin.

"Stop it," Sol clarified.

Sin obediently stopped it. After five minutes, he decided 'stop it' had to have run out already, and started all over again.


When Sol next got back to the castle, there was nothing much left for him or Ky to do but give in to the inevitable.

"I'm going to find someone to give you proper flag twirling lessons," Ky told Sin.

"Like the men with the big flags?" asked Sin, his whole face lighting up.

"Like the men with the big flags," Ky repeated.

"Whee!" Sin cried happily, swinging his beloved flag into the leg of Ky's desk so hard that everything sitting on it rattled.

"Sin!" Ky warned, "No more waving that around inside the castle, do you understand? You're going to break something if you don't stop it!"

Sol was napping on a chair when he heard the sound of Sin stampeding past, cheerfully calling out "The fuck off!" as he ran by on route to the flag-sanctioned zone of the outer gardens.

Oh fu… fudge! Sol thought. The odds Ky hadn't heard that …

"…Sol?" called a far too familiar voice from Ky's office.

…were zero. And that would be the sound that heralded yet another visit to the castle spent sleeping on the couch.


In a desperate attempt to attempt to fix the damage Sol was doing to their son's vocabulary, Ky gave Sin his own pocket-sized dictionary to take with him next time he left the castle. Sol might've rolled his eyes at this move, but Ky's icy remarks about his inability to even teach Sin to swear with correct grammar didn't leave him much room to argue. Sin himself was thrilled to by his new book. He was still at the age where every new possession became his favourite thing until an even newer toy to replaced it – whether it was a stuffed animal, royal flag or outwardly boring reference book didn't make much difference. He was also at the age where all children firmly believed that books weren't being read properly unless they were read out loud, and Ky had to have known that better than anyone. Within a few weeks of having to grit his teeth through listening to textbook definitions of words like 'discombobulate', Sol began to seriously wonder whether Ky had had ulterior motives behind giving Sin that dictionary which included some unusually creative forms of revenge.

The dictionary was also the first source which introduced Sin to the concept of what adjectives were. And as he discovered, to his delight, there were few things in the world that could be described by more different adjectives than non-humanoid Gears.

Not that even the world's most single-minded Gear hunter found many Gears around anymore. Still, even now there was always that odd one here and there that missed the memo about how Justice's defeat was supposed to mean they all stopped functioning and cracked out of its seal somehow – though most of them must have thoroughly regretted doing all of the above by the time Sol Badguy had tracked them down.

"It's a really big one!" Sin chimed happily, watching his Dad disentangle his sword from the latest such specimen's remains.

"Large-class. Nothin' special," said Sol. Dinner tonight was going to have to be fried Gear at this rate, but since the Gear itself resembled nothing so much as a giant pig, the idea wasn't as unappetising as it might have been.

Sin, however, thought there was far more that could be said on the subject than that.

"A big hairy, toothy, tusky, hoofy one!" he declared.

Sol glanced sideways at the Gear and wondered how much more of this he could take before it became unappetising all over again. "Looks like a pig to me."

"Porcine," said Sin authoritatively. "Can we catch a blue one next?"

"Sure, if we find one," Sol muttered distractedly.

"How about an insectoid, green one?"

"Same answer."

"A cyclopean, ovate one?"

"Haven't seen any of those in years."

"And a coruscating one?"

"What? Gears don't come like that."

"What about an oleaginous, anfractuous one?"

Sol actually stopped and stared at him. "You making words up now, brat?"

"Am not!" Sin argued. "It's right here in the dictionary, see?"

"Bastard gave you that thing on purpose," Sol grumbled.

Sin gave a whoop of battle and hit Sol in the leg with his flag.


"Sol? Unusual for you to contact me like this. What's happening?"

"What's happening? What the fuck did you…" There was an audible thump, a yell from Sol and the sound of a childish giggle which faded as the giggler ran away.

"Sol? Are you still there?"

"You. Taught him to hit me with that thing every time I swear."

"I did what? Sol, you're being ridiculous. You know he's always waving it around regardless of what gets in his way."

"Not lately. Flag waving cuts into his dictionary-reading time. Just when did your flag twirlers teach this brat how to aim?"

"Quite the opposite – every instructor he's had has done their best to explain to him that the objective is not to hit things, but it's an ongoing struggle. He must've inherited your talent for collateral damage."

"Why you…!"

"Are you sure you're not just imagining all this?"

There was silence, during which Ky thought he could actually hear Sol glaring at him over the phone.

"Although," Ky added, "if you're really worried, you could always try cleaning up your language a bit."

There was a click and then silence.

Ky could all too easily imagine the sort of language Sol would be using in his head for the rest of the day.

He wondered vaguely whether Sol had heard the smile in his voice as clearly as he'd heard Sol's glare. More than likely, he concluded, the smile widening even further.


No parent was ever so proud the day their child learned to electrocute themselves as Ky was. For that matter, not many children would have learnt to do so without ever going near a power socket, but Sin, as usual, was the exception.

"Lightning always has been a rare natural speciality even among Gears," said Ky, still looking inordinately pleased. "It must run in the family."

"Yeah, fine, and he looks like you too," Sol grumbled.

"I'll have to find time to teach him how to use it myself," Ky went on. "You could show him the basics, of course, but if you try and let him handle an element like lightning the way you manipulate fire, electrocuting himself is all he'll ever learn to do."

"You wanna make something of it?" growled Sol.

"Are you gonna fight?" asked Sin excitedly, enthusiasm not at all dimmed by his vaguely frazzled state.

There was really nothing that put a damper on a good match like a small child who cheered for both sides at the same time.


It wasn't until Sin was into the exciting world of greatly accelerated puberty that it occurred to either of his parents that there was a Certain Talk that they needed to have with the boy, which was becoming rapidly overdue. It wasn't that they'd ever mislead him about the question of where he came from – if anything, they'd been bluntly truthful about his unlikely beginnings. However, as far as making the boy understand how that sort of thing worked for normal human beings went, it was about the equivalent of a high-tech version of telling him that babies were delivered by the stork.

It was certainly an eye opener for Sin, especially considering Sol's blunt approach to the subject matter. The part where he had one more Dad than most other people was the least of the confusion.

"That's weird," he declared at the end. Sol shrugged at him.

"But," Sin protested, "most people are still made by mad scientists, right?"

"Hardly anyone. How many of those freaks do you think there are in the world?"

"Lots," said Sin emphatically. "Like, there was that one you took down last week. And that other one last year who made the big, evil, undulating jelly thing and the…"

"Quit reminding me," Sol grumbled. "Still not nearly enough of them for everyone to get born that way. Most humans just stick to the sex stuff."

"But you're not human," said Sin. "Didn't you get made by a mad scientist?"

"Kid, I was the mad scientist."

"…cool."


From then on, they were more or less into the countdown until Sin's furious growth spurt reached its end. When the day came that marked five whole months since they'd last had to buy him a longer flagpole, it was well and truly time to accept that that functional adulthood was on him at last.

"To think he's not even five years old yet," Ky commented, late one evening. Gear growth rates were something he'd never quite gotten used to in Sin's short life. "He's really no more than a young child, and yet…"

"…and yet he's as grown up as he's ever gonna get," said Sol. "Hell, would you card him if he walked into a bar?"

"You could walk into a bar with a real five-year-old and no-one would dare say anything," said Ky. "But then," he added, giving Sol a look. "I'm sure you've tested that enough times in the last few years."

"…maybe," Sol muttered vaguely.

Ky let out a sigh. "Well, it isn't as though I didn't expect as much."

"So I'm not going to get scolded for this one?"

"I do think I know you well enough by now to predict some of your behaviour, Sol," said Ky, wryly. "If I'd been that horrified by how you were likely to go about raising our son, I would've been a lot more reluctant about leaving him in your care so often."

He paused thoughtfully. "He does seem to be turning out alright."

"You would think that obsession he's got with beating me was a healthy sign."

"Competitive spirit," said Ky firmly. "Dedication to improving his skills. That's all perfectly healthy for a young man."

Sol gave a noncommittal snort.

"So, from here, I suppose he's just going to stay that age, isn't he?" Ky mused. "The same way you have ever since we met."

"That's how it works for Gears."

"You're both going to start giving me a complex about my age within a few years," said Ky, sounding wistful. "It already seems like a lifetime since our days in the Order."

"What, worried you're aging?" said Sol. "Hadn't noticed it."

"Your inattentiveness is not doing much to fix my wounded vanity, Sol."

"Well then," said Sol, with a dangerous smile, "Why don't you let me check properly?"

There was not much more talking done after that that night.


Another consequence of Sin's graduation from 'small, tagalong kid" to "grown up bounty hunter in training hey bring it on old man I'll take you down in a heartbeat!" was that the gap between visits to the castle started getting longer and less regular. The task of explaining infrequent visits from a young man who was clearly too old to be Ky's son and just as clearly too much like him not to be – accompanied by a man who'd officially been a wanted criminal since the Holy War – had not gotten any easier for Ky over the years. With Sol and Sin constantly on the move and most of his official channels unusable, even exchanging messages between them became increasingly more of a headache.

However, Ky was quite capable of coming up with more creative means when necessary – the incident with the Wanted posters being his best masterpiece to date.

"Hey, Old Man," Sin called, peering curiously at the photo on the poster, "isn't this your face?"

"Hah," Sol muttered, "bastard's always so indirect."

"But it's from Iluria!" Sin protested. "For a hundred million world dollars! They wouldn't be allowed to …"

"It's from Ky," said Sol. "One of his weird messages. He's summoning us home."

"He-eh. We miss a visit or something?"

"For a hundred million, it better be something pretty fucking urgent," Sol grumbled.

"So, important, super-important, serious, momentous or…"

"Oh, shut it," said Sol. "C'mon kid, we're gonna go see your Mum."

They tore the poster down before they left, just to be on the safe side, and turned themselves back towards home.