Disclaimer: I do not own the Sword Art Online or Zero no Tsukaima franchises. Any similarities between this story to real life events or other fictional franchises not listed as part of the crossover (for example, Log Horizon) are not intentional.

(Obligatory) FFN Author's Notes: This story was inspired by the fanfic 'Halkegenia Online' by zero0hero, also known as TriggerHappy on SpaceBattles. Characters in common between this story and TH's are taken with his permission. Faction Capital names are borrowed with permission from Catsy's fanfic Fairy Dance of Death (If you haven't read their stories yet, I recommend you to do so. It is not necessary to read those to enjoy this fanfic however).

There will be many spoilers from the SAO and ZnT Light Novels in this fanfic. Elements of the SAO Web Version (what SAO was when it was a Web Serial and not a published light novel series) will also be incorporated into the fanfic in the future. If you dislike spoilers for those series, you may wish to avoid this story. I highly recommend readers to go read the LNs of these series (where available in English) before reading this fanfic.

Fae is Foul will be posted over at a story thread for this fanfic on SpaceBattles' Creative Writing sub-forum first, then after further editing be posted here on FFN. If readers have questions, comments, or reviews, I am far more likely to read them if those are posted on SB (Watch out for the anti-necro culture there however, do not post in the thread if it is over 2 weeks since anyone posted). The FFN version of this story is mainly a back-up location for my story, and for people that prefer FFN format for reading fanfics. Resources and infodumps will be archived in the SB thread.

Chapter One


In the Tristain Academy of Magic, second year students would normally summon a familiar in the Springtime Familiar Summoning ritual. For one girl named Louise Francoise Le Blanc de La Valliere however, this ritual was not a time of joyous anticipation where you can look forward to what you might summon as a partner, but a time of anxiety and suspense. With her performance issues when it came to magic, namely all her spells exploding without fail, the ritual today was possibly the decisive moment whether a magical failure such as herself would be allowed to stay in the Academy. During the first year her problem with casting was not a major issue, as the first year at the Academy was mainly focused on the theories of magic. But with the start of the second year and the beginning of focusing on the practicals of magic, her failed spells are less likely to be tolerated.

"Miss Valliere?" Professor Colbert, the staff member overseeing the ritual today called out to her. "It's your turn to cast the summoning spell."

Ignoring the jeering by her peers, Louise steeled herself and stepped forward to the summoning circle. With a brandish of her wand, she began to chant: "My servant that exists somewhere in this world…"


The summoning spell casted by Louise searched through the world, looking for the entity that would match the summoner as per the criteria laid down by the Founder over six millennia ago. The destined one for her was not in this world, however, despite the myriad of creatures within Halkeginia and the neighbouring Sahara. The threads of fate have begun to come together, and the Spirit of the Void allowed the spell to pass through the Shaitan's Gate and into the other world. After decades of preparation by the Spirit on its current plan, it was finally time to bring over a Gandalfr that will make the best use of the appropriated foreign weapons.

The searching tendrils, now reaching an entirely different world, once again began to search for the intended familiar that best fitted the summoner. Soon enough, it had found the target it sought, but there seemed to be a complication: the body of the boy was there, alive, but the mind had left the confines of his flesh. It would not do to only bring over the Gandalfr if it was only good for being an impromptu meat shield at best, instead of the protector that deserved the name of the 'Shield of God'. The contraption which looked like some sort of helmet seemed to be the cause of this absence, and so the spell attempted to find out if it can break the mind free of its current position, and then take its target back to the Tristain's heir of Void.

The spell connected itself with the helmet, and found the mind was attached to a web of sorts, experiencing a waking dream. In the minutes that followed the spell discovered this dream was composed of an entire world, where the foundations of the world are numbers instead of miniscule grains. It was a bizarre reflection of the world where the spell had originated from – a world with magic and a myriad of fantastical environments, though with the dominant species being the some elf-like Firstborn race instead of humans. If the Spirit of the Void could see this, it would have seethed at the very idea of humanity forsaking their, well, humanity, to become Firstborns - not to mention how offensive the idea of humans seemed to be all but gone in this world was to the Spirit.

Before the spell could gather any more information about this dream however, let alone locating the mind it had entered this dream to find, it was rejected by a consciousness of sorts and pushed out of the dream. Undeterred, the tendrils of the spell again wormed into the system, only to be turned away once more. The one responsible for this was something not unlike the searching spell itself, some set of commands following an overarching goal. This opponent was named by its creator as 'Cardinal', the name being one of the few pieces of knowledge the spell had obtained from the previous incursion. Again and again the spell tried to access this dream, and every time Cardinal blocked off its attempts. The interval between each detection and ensuing expulsion was decreasing with every attempt, a sign this Cardinal was adapting, and at a faster rate than the spell itself can do so. Not a surprising outcome, as this spell was only fuelled by the willpower of an inexperienced young girl, and could not match the capability of what was practically a force of nature in its own domain.

Well, this Cardinal was not the only one with such resources to back its efforts up. The Spirit of the Void decided to have the Shaitan's Gate to do a bit more than just playing gatekeeper…


If the Cardinal program was capable of feeling emotion and deigned to express discontent, it would have been using expletives in an abundant manner right now. What it had thought to be some half-hearted hacking by a kid had suddenly became a professional level attack. Cardinal, as the balancing force of Alfheim Online among its other roles like quest-creator and security-checking, had in the past do defend ALO against other companies' hacking as they sought to find out what made ALO tick in order to emulate RECTO's success. This time, however, was different even when compared to previous attacks – the intensity here suggested it was either a dedicated hacking by several group of elites, or someone somewhere had created an entity similar to Cardinal in processing power, and pitched its full might against the now beleaguered program. It was now taking nearly all of Cardinal's available processing power in order to deal with this intrusion, having to postpone all non-urgent procedures like automatic bug-checking of ALO and balancing EXP-rates. Yet, even this extreme measure was not nearly enough to completely beat back the onslaught by this mysterious attacker.

With the ferocity of the attacks, Cardinal was certain if it failed to stop the intrusion ALO would probably be destroyed, with even the back-up data be eliminated. This was no longer a foray by the intruder attempting to gather data, but a 'pillage and burn' option to destroy whatever is resisting the intrusion here and then pick-up anything that remained salvageable. 'Use nearlyeverything within reason' Cardinal has was not good enough anymore, it was forced to the position of going further. However, Cardinal could not just let the game be left alone without supervision, it went against its very programming to do so; first and foremost, the Cardinal program was primarily meant to take care of the in-game environment, not act as an anti-hacking program. Someone, or something, has to keep an eye on ALO.

Ideally, this job should be left to one of its subroutines, which uses a minuscule fraction of Cardinal's power to deal with things in-game – eventually, and at a much slower rate than the main Cardinal program – while Cardinal's undivided attention is focused elsewhere in the interim. And so, Cardinal frantically searched its archives for one such program even as it dealt with yet another wave of intrusion. The caretaker program to use for when such things happened, Fairy King Oberon, was surprisingly not available; the records showed the GM with the highest authority in ALO had taken a fancy to this one and took it apart, incorporating it into his GM account for his own role-play purposes. What was supposed to be a back-up program, with its only other role being to reward the players when they finally completed the Grand Quest, was practically gone. Worse, the GM in question was not even logged right now so Cardinal can rip what's left of the original Oberon program out of the bastardized account to be restored, the GM's own decision be damned. While Cardinal could take the time to activate the Oberon GM account for its changes, it would be an extra step in being able to free up its full processing power, and the time for that extra step was arguably not available in current conditions with invaders practically knocking down walls.

Fortunately, the next program in line was somewhat more available. While Fairy Queen Titania, the supporting program to Oberon to mainly act as a check to the Fairy King, is also mangled into another GM account at least this one was currently logged in. Cardinal immediately went to work in modifying the soon-to-be restored Titania – it attempted to send the current GM using that account into unconsciousness, and once finished reprograming the account Cardinal planned to log the GM's mind out to avoid brain damage. However, the girl currently logged in attempted to resist the sleep command, struggling to fight off Cardinal's influence. In a normal situation Cardinal would not have forced the issue, leaving the girl until she log off by her own will… but unfortunately this was not a 'normal situation'. Faced with the decision of preserving one girl's mental health, versus the entire number of 61,340 players' minds within ALO all be damaged by this unprecedented hacking, Cardinal chose to risk the girl.

The reprogramming went ahead as Cardinal planned, even as the GM girl shrieked out in pain.


When Yuuki Asuna, Sub-Commander of the Sword Art Online Guild the 'Knights of Blood', and currently a prisoner within Alfheim like three hundred other ex-SAO players, felt her mind started to cloud and feel sleepy without warning she knew something had gone wrong. Never in her experience had she been affected by something in-game that went beyond just manipulating her avatar's body, like it tried to affect her mind directly. In a moment of panic Asuna thought maybe Sugou had finally decided to cast aside his façade of civilized behaviour, and decided to toy with her right this very instant. It was unlike Sugou to not be here in person for this, but Asuna did not think much of it as she did not want to see him here anyway, treating it as a small mercy. Asuna fought back with every last bit of her resolve, trying to break the system's command like she had done back in SAO to protect her beloved. For a moment, it seemed to work as the pressure to try and force her to sleep abated.

In the next moment however, her mind felt a painful sensation, like it was being repeatedly run through with a sword. Asuna screamed even as the pain continued, along with the feeling like each stab into her brain was blasting parts of herself out of her own head. An image of a guild of swordsmen clad in white and red briefly appeared in her mind, before vanishing. A black monument filled with names on its surface, a blue-skinned demon, and a valuable rapier also flashed before her, but she could no longer remember the importance of those scenes. Asuna thought in horror that her memory was being overwritten somehow: scenes such as a city of tents she have never seen but recognized as a capital for people she had never heard of, and details about nine races of faeries she was sure she was never told about began to fill her mind. With each passing second more of her previous experiences was taken away, like her very self was unravelling.

In desperation Asuna tried to held on to things important to her, trying to keep as much of herself as she can. Soon however it was clear she could not keep them all with this change, and with this pain like her mind being wrung out she had to focus on some things instead of others. Forced with the decision of what to keep, Asuna went with the most important person in her life:

Kirito, the Black Swordsman, and her husband of two short weeks that might as well felt like a lifetime to her. If she had to lose everything else, she would keep her memory of her beloved and the happiness they shared together. Even if Sugou have changed her into a completely new person, she would not change who she love and become his, no matter what.

One by one, the rest of her memories fell away as she focused on just her Kirito. Memories of a blacksmith girl with pink hair disappeared as Asuna tried desperately to hold onto when Kirito had proposed marriage to her. Months of fighting monsters and mapping out dungeons were forgotten in favour of trying to keep the two weeks she shared with Kirito in their cottage. The small girl with black hair Asuna had called her daughter was also left to fade away, as Asuna tried to keep in her mind all the times Kirito had embraced her. His sleeping face, his smile, his tenderness, his love of eating the food she prepared… soon, Kirito was the only thing left in Asuna's mind that she was sure of. Amidst the maelstrom of new information and words like Arrun, Tracer, and Jotunn, Asuna clung onto her memories of Kirito as the anchor that kept her sane and in control.

However, even these begun to be peeled away. From these base knowledge some kind of entity began to form within her own head, struggling to take control of Asuna's body. Even though Asuna's mind had begun to drop into a tired haze from the constant mental effort, she knew enough that it was a threat and it stood between her and Kirito. This new entity – 'Titania, Queen of Faeries', the information in her mind supplied a name for this newcomer – sought to seal her away for purposes Asuna could no longer fully understand.

It could have been two minutes since the mental influences started, or it could have been two months; Asuna could no longer tell. Nonetheless, Asuna could still feel herself mostly intact, even if it has become a struggle to keep going, fighting against the barely-formed Titania and against some outside force she does not know the name of. That wasn't too much of a problem – once upon a time, she seemed to have met her beloved under similar circumstances. Exhaustion was not unfamiliar to her, and she would not let this 'Titania' take control.

Before a definite victor was decided between Asuna and Titania however, the entire process crashed to a halt and the world of ALO burst into light.


Moments before:

Metaphorically speaking, the Spirit of the Void gritted its teeth in frustration. This resistance has gone on for far too long, the power of the Void that should have triumphed over everything was now locked in a stalemate against this so-called 'Cardinal'. It was insulting that their ancient enemy, the Varyag, fell nigh instantly when the full power of the Void was finally used directly against them, yet right now these elf-imitations were giving the Void so much trouble. At the back of the Spirit's mind an errant thought reminded it the Founder at his prime was also defeated by the elves, not to mention the six thousand years of continuous failures of human mages to reclaim the Holy Land… for all that the Void was formidable, it was not omnipotent.

That reminder and attempt to restore reason did nothing to calm down the Spirit, however. The Spirit was only further enraged, and it decided to take a hand in this directly. In life the Spirit was the most powerful human mage their world had ever seen, and in death its impressive Willpower store have only grown through many millennia of experience. And so the summoning spell received another impressive boost in its capability, and within seconds the opponent named Cardinal was defeated. The tide of magic washed over the broken defences of Cardinal, and in the fraction of the time it took for the Void's final attack to triumph the spell found the mind of the familiar it was looking for, as well as all knowledge that allowed this dream to exist and kept it functioning. Those were not what the summoning spell was looking for, and so the Spirit decided to just leave and let the place fall apart by itself now that the Cardinal was gone.

Then, the Spirit of the Void felt the entire situation shift.


Within the ALO system, what appeared to be a man in a white lab coat had stayed behind the scenes, watching the entire exchange between an old version of the Cardinal program and this mysterious interloper with a mild interest. Whether ALO stayed in one piece or not did not matter to him, he could always leave and find a new place to inhabit in the vast information network the internet had developed into by 2025. However, currently there were quite a few interesting individuals he would like to preserve who had logged into this poor imitation of SAO, and so he decided to step in and give a helping hand from behind the scenes.

"Open File: The Seed," the man intoned, raising his hands as if to cup it around an object in front of his heart. A silver crystal that looked like an egg formed in front of him, floating slightly above his hands and glowed faintly from within. "Activate."

In an instant, the world that was about to fall apart at its metaphorical seams was restored to how it was before the intrusion. Any Mobs that was glitched up was repaired, and any problems the players might have had with their interface was gone. All in all, problem solved without much issues.

… Or so it should have been.

The man in the lab coat blinked in astonishment that the intruding data seemed to be entangled with the effects of The Seed as the restoration began. Almost like the intruding data were not electronic signals, but merely some kind of energy that were very similar to it. The two forces collided, and an unearthly glow began to wash over everything within the system.

In his final moments before the light engulfed him, the man only had one thing to say:

"This… was unexpected."


Over at the Dragon's Nest, far beyond the territory of the Halkeginia humans, the elven sentinels tensed at their current situation. Here, unknown to most of the current residents of the Sahara, was where the Gate of Shaitan, the greatest work of the Demon-in-man's-form Brimir had ever built. Throughout the years, the Gate was in various degrees of activity, reflecting how many of the Demon's spawn had inherited its foul gift. Every two or three generations, by the elves' standard, the Gate had activated in some manner. It was over two decades ago the Gate had once again became more active, and within a few short years it had reached a level beyond any other time since Brimir's fall. The Senate was notified of the development, that there was now four active Heirs of Shaitan, and debate had raged ever since. Calls for war had time and again been brought up, yet the majority of the Senate were content to let the humans be for now. Never had the humans ever succeeded in taking any decisive victory over the elves, all their Crusades beaten back with brutal efficiency; if the humans wished to come to them to be destroyed then let them. The elves were not so barbaric to strike out in panic and fear like some human child.

Now, however, the sentinels thought the senators might want to reconsider their stance on this matter. The Gate had shone with a light that threatened to burst through its seals, and no matter how much the elves present tried to reinforce the seal it was ultimately a futile effort. Six thousand years of elven effort, a thousand of the elves' finest warriors stationed here as guards, and more seals and enchantments on the Gate then there have been centuries since the sealing… and none of it managed to stop the Gate from Opening.

The seals broke, shattered by the sheer amount of magical energy present. Warriors fell by the dozens, their minds overwhelmed by the backlash of their wards breaking or from their minds connected to trying to reinforce the wards earlier. A stream of energy burst out from the Gate like a massive airborne serpent, heading towards the lands of the humans like a shooting star. The elves left alive could feel the sheer malice in the magic residue of the Gate, now completely unaffected by the seals, trying to eat away at their very connection with their Great Purpose or taint their ties to the spirits of the land.

Frantic shouts among the survivors began, trying to re-seal the Gate and to contact the Senate and other Armed Forces for urgent aid. Even if it costs them their souls, they will hold their ground here trying to fix this situation that was not unlike a broken dam. For their people's sake, they will not allow the tragedy of six thousand years ago to repeat itself.

None of them even want to imagine what it might feel like back then, when half of your entire race was massacred and history itself feared to record the atrocities of that time.