[Futanari, Feminization]

Night had fallen on the Chaldea complex. Ordinary humans, provisionary Masters, as well as the Servants that they commanded had all turned in. All except for one cheeky little black-haired lad, who had waited for oh-so-long.

"This is it..." The young man, commonly nicknamed Gudao for his hand in solving the Grand Orders, carefully crawled out from underneath a specific bed in the complex. A bed belonging to an equally specific Servant, the Japanese heroine Minamoto no Yorimitsu, more commonly known amongst the Chaldeans as Raikou. He knew that on this very night, she'd be spending time cleaning up trash in one of the tiny singularities that popped up every now and then, so his time to 'strike' was now..!

The boy climbed onto his knees as he approached the drawer that would contain the most precious treasure in all of Chaldea. More revered than the holy grails that had caused the Grand Orders. Worth much more than anything that dinky old Da Vinci could paint. The very epitome of sacred, beyond even that of Jeanne d'Arc's presence...!

He pulled out the drawer, before sinking his hands down and pulling out the lacey prize within. Raikou's used underwear, dumped into the exact same pile of identical panties. Gudao had strategically told the older Servant that they didn't actually wash their clothes, which meant that she was keeping everything in the same room... and this meant that he had all the time in the world to enjoy the musk that a woman like her would naturally leak onto her underwear...

"Raikou's smell... nnnnnnhhh..." The tent that pitched in his underwear was obvious as he brought the fabric up to his nostrils, taking deep whiffs that caused his pants to grow rather wet in mere moments. To think that a young man could cum from just the scent of a woman like her...

Gudao reached down to grasp at his tenting cock, furiously pushing and wrapping his fingers up against the rod as he tried to rather plainly fap to the best of his ability. He wanted to cum to the scent of the motherly servant that doted on him without him even getting close to asking...

However, he noticed something awfully strange about the smell. There was the distinct element of the motherly Servant's feminine musk, yes, but there was also an additional bit he hadn't expected. Namely, the faint smell of precum. Not the kind of clear ejaculate that a female would produce, no, this was the proper kind that only a cock could shoot out.

Did Raikou have a cock? The question bounced around in his head as he imagined the older Servant in her Berserker form, revealing the bulging outline of her rod up against her bodysuit upon being prompted. He knew that she wouldn't agree to it when they were in public, but the thought of being able to see that motherly woman shivering with pleasure as her member grew erect was more than enough to get him edging more than he already was, especially as he drew another few whiffs of wonder from the used underwear...

"Ara..."

Then a thunderbolt pierced through his body, practically petrifying him as he was caught within seconds. He did not dare turn around, fearful of peering straight into the eyes of the one that had discovered him red-handed. "R-Raikou... I... Iiiii... IIIIIIII!" To make things that much worse, the fear that pulsated through him pushed him straight across the edge, as the panic that had settled into his body did nothing to alleviate his arousal.

The purple-haired Lancer that had taken up a spot behind him grimaced as she heard the uncouth sound of cum squelching forth into boxers. "Master, you awful man..." Raikou's voice was usually pleasant to the ear, but hearing her sound so disappointed in him was enough to make his entire body unresponsive. He wanted to run away, to avoid whatever punishment she might have in store for him, but he just absolutely couldn't.

While the young Master was frozen in fear, his authoritarian Lancer pulled open one of the other drawers in the cupboard he was digging through. A slight grin made its way onto her face. "Master. Strip. Unless you want me to make your predicament worse than it already is." Her firm tone made it hard to disobey, and her firmer glare just added on.

Moments later, Gudao's clothes fell onto the ground, every single individual article, revealing his lithe body in all of its glory. He wasn't kept uncovered for long as a set of clothes were thrown straight at him, an exact copy of the motherly Lancer's outfit. "Wear these, if you like my underwear so much. Perhaps we'll see how well you fit them." Raikou's tone maintained that firm edge, although now there was a certain undercurrent of desire filling her voice as well.

With good reason too, given the way her skirt was starting to lift up rather impressively so. To avoid his motherly Servant's wrath, the Master hastily threw on the individual pieces, until he too was dressed in the exact same sukeban uniform as her. The only difference, being how much the two were tenting their underwear and skirt. And of course, the lack of feminine curves on Gudao.

Raikou carefully strolled around the young man, licking her lips slightly as her gaze continued to make the boy's rod grow and pulsate with need. "Ara. To think such an awful boy like you could look good in a girl's uniform. I really do have to punish you for this, Master..." She gently whispered as she parked herself right behind him, rod pressing up against his nearly exposed rear. She didn't wait for him to give even the slightest bit of permission before she shoved her hips forward.

A piercing scream filled the room, which did nothing to pierce the soundproofing that laid within the walls of every part of Chaldea. Nobody could hear him moaning like a girl as he was having his ass pounded. Her cock went in, out, repeating with every moment that passed. She was moving with the pace of a jackhammer while outputting the power of a freight train.

Nobody should be able to endure this, it should feel awful and it should kill most of any human with how much strength laid behind the thrusts. And yet, he remained hard and struggled to even get limp as the tip of his rod slowly started to leak a clear bubbly liquid. "You're the worst, Master... You're getting hard from having your dear Mother mess with your manly hole. Maybe you're not such of a man after all..." 

Her humiliating and degrading words just made the boy edge closer and closer, to the point where he came in such a futile manner, the cum gathering in the front of his frilly underwear as it soaked into the fabric. Far before his Servant reached her own climax. She could only chuckle as she felt his body tense up from its first anal orgasm, prompting her to play with his ear a little using her tongue and teeth.

"Oh, Master... Doesn't it feel wonderful? By the time we're done tonight, you'll understand what kind of person you really are..."

The screams that echoed throughout the room intensified and multiplied throughout the night as they gradually turned from pained pleasure into earnest devotion towards the woman who was showing him the proper way...

Nobody knew what had happened during that night, but they would definitely be shocked to see him afterwards.

---

"Senpai, you look..." The velvet haired demi-servant paused as she spoke, her eyes carefully examining the black-haired youth a few times.

"I look what, Mash?" The feminine tone that left the Master's lips was unbecoming of him, and as were many of the other traits that he now displayed. Most prominently, a set of breasts that definitely didn't seem fake... Not to mention a skirt that left barely anything to the imagination and hair that reached all the way down to his surprisingly squishy-looking ass... Just what had happened the night before?

Mash shook her head as she swallowed the thought she was about to vocalize. "Never mind. It's not important." She sighed a little as she brushed her concerns aside, only to smile once more. "Well, how about we get going with today's missi-"

Right as she was about to finish, she felt something awfully soft brush up against the back of her head. "Oh, there you are my little ones!" That voice was unmistakable, no doubt belonging to a certain Berserker-turned-Lancer. "You weren't planning to head out without your Mother, were you?"

The blush that covered both Mash's cheeks as well as Gudao's was more than obvious, but the Master was the first to speak up. "Oh, Mam- I mean, Raikou. I was just about to come by and get you!" His smile wavered a bit as he spoke, while his legs pulled him towards the mature mother's side. "I-I think it's best if I just go handle the missions with Raikou today, Mash. I'll see you soon, promise!"

As quickly as the sukeban-clad mother had arrived, so left the Master with her by his side leaving the Shielder demi-Servant behind. Mash adjusted her glasses as a sense of envy started welling up within her head, but she couldn't bear to voice her concerns... at least not at the moment. It would be extremely rude to stop him from doing his job, just because she was feeling something as silly as jealousy.

Especially as she caught the glance of something white and sticky dribbling down her Master's inner thigh...