[Feralization, Semi-Twinning]

Within the halls of Chaldea, the last stronghold of Humanity, there were many different personalities and ideologies that often crashed and clashed against one another, with their opinions flying wildly around the place. Some got along, some hated each other beyond all reasonable belief.

And then there were some that got entertainment out of it all. One of those people was the delightfully devilish BB, who had the audacity to prank one of her fellow Servants using a fake Grail that she had cooked up using data gathered while she was in control of the Moon Cell. Now, it had all the same properties of the usual Holy Grail, but it was boobytrapped to ensure that she’d have a spectacle to behold once it was all said and done.

Finding somebody to dump it on wasn’t hard either, because there was exactly one Servant nobody dared look at for more than a few minutes due to her eccentric personality. Jaguarman, the Pseudo-Servant that used Fujimura Taiga as its host. She simply left the cup at the doorstep of the Lancer’s doorstep and skipped off, hoping that the woman could raise enough hell that she could have Master all to herself.

She’d soon find that she might’ve just committed the biggest mistake a girl could’ve ever made.

---

The Ginger-haired Lancer narrowed her eyes as she looked at the cup that had been left outside her door. The strangely golden and otherwise unremarkable cup. They hadn’t even left anything in it for her, was somebody playing a prank on her and cheaping out on the actual prank?

“Hrrrmmm… What would I need this thing for?” Jaguarman, or rather Taiga thought aloud as she prodded it a few times, wracking her brains for answers. It didn’t seem useful, and she never heard talk about a cup. Sure, there had been talks about some sort of Holy Grail or something, but that wasn’t a cup. That was a grail. There was a fundamental difference between the two!

The tiger-clad woman picked the cup up and chucked it at a wall, trying to see if it was durable or not. When it bounced harmlessly off without even a dent, then she started thinking it might be worth a damn. “But who would leave a perfectly good cup laying outside my door?” She scratched her cheek idly with her plush claw, humming to herself as she picked the thing back up and stared into its bowl for a few seconds…

Only for a strange feeling to well up inside her. A wild feeling, like she was back in the jungle and ready to hunt down her prey. A feeling that couldn’t be satiated by just anything! She tried to pull her eyes away from the cup, but it just drew them back in and made the feeling intensify. It was overwhelming, overbearing, and most of all irresistible. She just wanted to listen to it and show somebody what it meant to be wild..!

Almost as if on cue, a perfect piece of prey showed up at her door. A familiar enemy turned ally and somebody that looked a little too peeved to be walking around at this hour. The purple-haired snake, Gorgon. “Jaguar! You told me to come here so I can be taught how to defeat you, and you’re just playing with a grail!? Face me l-” The Avenger made a double-take as she realized what the woman in the tiger suit was playing with, infuriating her further. “YOU, OF ALL PEOPLE, HAVE A GRAIL?” The fury seethed through her words as her snakes lifted themselves up to be eye-level with the rest of her face, each of them glaring hell down on the woman on the floor…

Taiga didn’t care that she was being shouted at, far from it. It was exciting. It meant that her prey was going to fight back. She loved a good challenge, especially if she was going to imprint this wild feeling on them. All she’d need to do was just beat her up, and she could teach her what she needed. The ginger-haired woman flashed a wicked and fanged grin as she turned her head to look at the serpentine Servant. She didn’t even need her weapon for this, her dull claws would be enough!

Gorgon didn’t like that look in the Lancer’s eyes as she grit her teeth. She would defeat her right here and now, and then report her to their Master. She had clearly stolen a grail from the stash without asking and was about to power herself up. That was against the rules, and the only reason she knew that was because she had clearly already tried it herself and gotten lectured over it multiple times!

The purple-haired Avenger tried to lash out against the woman that was creeping along the ground, but that just triggered the latter’s counterattack. Before she had a chance to strike a decisive blow, she suddenly felt a claw sinking into her face, causing her to back off and cover up the wound, only to notice that there wasn’t any sign of a wound. In fact, she could hardly feel any sort of impact actually having been made on her face. “What in Zeus’ name…”

Taiga tugged her hood over her head to appear ever slightly more intimidating as she pounced once more, this time knocking the oversized snake to the ground as she mounted her. Her breath was warm, and her intent to kill was palpable. But that intent merely masked what she had in mind for the snake, who was struggling underneath her…

“Unhand me, you simpleton!” Gorgon shouted, but that just earned her another swipe across the face which did nothing more than anger her given the fact that it left no wound behind. Sure, it hurt and it pissed her off when she got hit, but there was not a single shred of evidence left behind after the hit. Despite her Monstrous Strength, she wasn’t even able to knock the feline woman off either, serving to further increase her current rage at the situation…

What the Avenger didn’t realize, and neither Taiga consciously for that matter was that every strike that the ginger-haired woman inflicted now served to awaken the inner Jaguar within the person. If they didn’t have a Jaguar within them, it wasn’t a problem. It would awaken within them regardless and consume them from the inside out until there was nothing left besides a Jaguar on the hunt for her prey.

The Jaguar continued to strike away at her prey, regardless of how many times she shouted up at her or tried to struggle. None of her struggles were worth anything under the might of a mighty predator like her. It was even more evident in the way that the Avenger’s hair was gradually taking on an orange shade that perfectly matched the Jaguar’s hair, and she even gained a couple of cute wild whiskers on her cheeks, making her look more like a wild animal.

Gorgon’s thoughts were scrambling the more she was being hit, not even noticing that she was starting to look like a slightly different version of the Jaguar. Which made sense, her own Jaguar was being awakened…

But, what was a Jaguar? What was a Gorgon, even? What was she? Her heart said she was a Jaguar, a proud predator who was going to roam the lands and hunt the prey she deserved while answering to the Alpha Jaguar, the one who was currently slashing her face to bits. It was what a lower Jaguar like her deserved, a rite of passage if you would.

As the serpentine woman’s scales slowly turned into fur to fully accommodate for her new status as a Jaguar, the snakes that acted as an extension of herself faded away and became mere parts of her hair, leaving her looking just as wild as her Alpha if not more genuinely so considering the oversized suit that the woman wore.

Once she was satisfied with the changes that the other Jaguar had undergone, Jaguar got off her former prey and licked her cheek, accepting her as another one of her kin. But even though one had been changed, there were still many more that needed their inner Jaguar to be unleashed upon the world.

Thus, her keen predatory eyes fell upon the trinket that had corrupted her, and a smile grew on her face as she made a single wish that would cause all of Chaldea to fall…

---

Elsewhere, in another part of the Chaldean complex, a certain King was having a discussion with her Master’s most loyal servant, partly about their pasts and partly about how the latter could improve her combat skills so that she may defend their Master more effectively.

“Mash.” Saber, or rather Artoria Pendragon, spoke up as she held her sword in a combat-ready stance. “To properly defend your Master, you must be ready for anything. Merely seeking strength for the sake of it won’t help you in your duty.” The stalwart king explained as she raised her blade. “I shall test your strength, block my blade until your knees give way!”

The purple-haired Demi-Servant, Shielder alias Mash Kyrielight, nodded as she held her shield upright. Almost immediately she felt her legs giving way thanks to the flurry of blows that impacted her shield. But she couldn’t just give up, that’d mean she’d disappoint her Master! Her Senpai! She had to do anything in her power to stand up to the assault…

She braced herself for the impacts as they came, not realizing that they were growing wilder and more intense as the seconds passed by. At the same time, her guards were getting stronger and less taxing on her body, almost as if her defenses were increasing naturally. She didn’t realize that her inner Jaguar was in the process of awakening thanks to the wish that Jaguar had made on the grail, nor did she realize that she had just grown a couple of cute jaguar ears atop of her now-orange-haired head.

What Mash did realize, however, was that defense didn’t matter at this point. Her wild whiskers were flared as she threw her shield away after the last strike before pouncing atop of the King that had been hammering away at her shield, intending on finishing her off right then and there…

Instead, the Jaguar Shielder received a brutal cut on the face, leaving no mark while forcing her to back off and let Artoria get back up. She threw away her sword as she proudly showed off her body, which had been awakened just the same. Gone was her armor, replaced with a delicate layer of fur that cupped her body in an erotic fashion, a look which was completed with her own whiskers and ears as well as ginger hair. The two of them had completely awakened, and it was all thanks to the wish of somebody neither of them cared about.

The two Jaguars bared their fangs as they leaped at one another once more, intending on settling their fight then and there. Instead of training, they were now in a fierce competition to determine which of them was the Alpha of the relationship… and neither of them were about to give up without a good fight…

Many other pairs across Chaldea were experiencing similar incidents, with their wild sides ignited by the wish that was sweeping throughout the complex. Before dawn would strike, the entire thing would’ve been turned into the hunting ground of an entire legion of Jaguars…

And there was exactly one girl to thank for all of this...

---

“Heh! This is really something, I didn’t expect that crazy Teacher to cause everything to turn into a zone of pure wild carnage, but here we are!”

BB was laughing and reveling in the chaos from the safety of her room, having hooked up plenty of screens to the camera network. Servants became Jaguars en masse and they couldn’t do a thing about it. Some of them realized that things were going horribly wrong, but that didn’t stop them from falling prey to the wild sensations spreading through their hearts as soon as they let their guards down.

She was different, of course. She had put up a firewall around her body to ensure that she couldn’t be affected by the Grail. Not that she needed it, she was an advanced program, defending herself against a simple trick that the world was trying to pull on her wouldn’t be hard.

“Aaahhh… I wonder when they’ll realize there’s prey to mess around with…” The purple-haired Moon Cancer chimed to herself as she flicked through the cameras, humming as she tried finding an interesting pair that hadn’t yet succumbed…

Then she landed on the camera that showed her Master’s room, and her heart suddenly froze. She… she had just unleashed a bunch of predatory women that wanted to play around with their prey, and her Master, the adorable little Gudao, was one of them. How could she have done such a thing?

Sure, he wasn’t nearly as cute or as amazing as a certain other Master had been, but he was still her Master! He was hers! He… He looked so delicious, like the perfect prey. She understood perfectly why any kind of Jaguar would want to go after him, and that’s why she lamented her own egocentrism. Because of her mistake, she had just doomed him to a fate that might be worse than death…

But if she was the one to prey on him… If Jaguar was the one to prey on him, then it’d be alright, wouldn’t it? That line of thought soon consumed her, preventing her from realizing that her ‘firewall’ has crumpled against the might of the Grail, changing her into a Jaguar like everyone else. She got the entire package too, in the form of cute ears, her hair having taken on the ginger shade, a couple of menacingly cute whiskers, and even a set of starry irises in her eyes, a reflection of the Alpha Jaguar’s eccentric nature…

Now, she just had to keep a watch on him. She could do that. She could watch him all day, drooling over the prey that she craved so much… not realizing that she was leaving him utterly defenseless in the process. But it’d be alright….

The Alpha would take him…

---

Gudao woke up hours after it had all started, yawning softly like he usually did. He was a sound sleeper, you’d really need to shake him about to get him to react in any way, so it wasn’t a surprise that he had slept through it all.

What was a surprise, at least to him, was finding a certain ginger-haired woman in a fursuit laying atop of him with a devious and predatory grin on her face. He knew who she was, but the way she had approached him while he was sleeping was weird. “T-Taiga?” He asked, hoping that she would respond…

Only for her to pin his face between her ‘paws’, causing him to let out quite the loud yelp as he felt something leaving his mind. He didn’t understand, he didn’t understand at all. The only thing he understood was that he should be afraid of the Predator above him. The Jaguar that lusted after him like he was her Prey…

Wait, Prey? Wasn’t that who he was? His mind was tearing itself into bits, partly from the fear rushing through it and partly from the way his face had been smooshed by her paws. Or... was it fear? He couldn’t tell at this point, he just knew that she made him feel something. Wasn’t he supposed to feel it because he was her Prey?

Jaguar licked her lips as she watched the Prey struggle to accept his new role. He’d understand. It wouldn’t take long, especially as any type of muscle definition faded from his body, making him look weaker. It also helped that his hair took on the same shade as the Jaguars, marking him as one of theirs. And to really complete his look, he shrunk ever slightly, really making her tower over him for the full dominant package.

The Prey shivered all over, whimpering like a frightened animal despite the clear wet spot in the underwear that he still wore. A sign that he was ready to be taken. A sign of a good piece of Prey. So it was no wonder that the Jaguar forced herself upon him, pulling the covers over the two of them as she went to work…

Whether Human or Servant, the Alpha Jaguar had changed them all irrevocably. With the Master giving in and becoming her prey, Chaldea had well and truly fallen, becoming a paradise and hunting ground for all the Jaguars that now roamed its halls. What would become of Humanity? They didn’t care, they just wanted to satiate their wild urges to hunt and to prey upon the weak…

To think all of this was caused because of a little malicious cup.