A Fate/Stay Night Transformation Story

(Male Second Person Age Regression)

“Hello, Master. Are you ready for dinner?” Caster looks to you with a small smile on her elven features. Her pointed ears twitch freely, the hood she usually sports down around her collar instead.

You still don’t fully understand the principles of his Holy Grail War, but you do understand the gist. She is your Servant, and so will do anything to let you win the war. Those are the rules, at least as far as the priest explained to you.

Really, it could be worse. You get to fight in some kind of ghost deathathon, and on top of that you’re partnered with a beauty. Better yet, she seems to want to play by all the rules, which is just fine in your book.

“Dinner would be lovely.”

She seems inordinately pleased by your remark, and you allow yourself a contented smile. You slip into the chair at your table, a Western indulgence that you’ve kept despite moving to Fuyuki. In turn, she slips a plate before you.

The steak still seems to sizzle on the plate, rich juices flowing across its marbled surface. It’s flanked by a small buttered potato and some peas on the other side. Truly, she’s outdone herself. Somehow, she knew just how to make a dish fit for royalty.

You comment as such, slicing a sliver of meat and popping it into your mouth. It’s almost magically good, and a tingle runs through your whole body. You look up to Caster appreciatively, and find that she’s delighted by your comment. At least, you assume she is. There’s a smile wide on her lavender lips, and she keeps glancing in your direction with a flushed look on her face.

You didn’t realize it before, but sitting in this chair makes her look a bit taller than you. You muse on this fact as you have another bite, wondering if your Servant is going to join you in eating. You suppose not—the mana you provide her is sustenance enough. Probably.

“Please, allow me.” Her hand reaches across the back of yours, and you pause mid-cut. A slow smile dawns on your face as you realize she’s been waiting to feed you, and you look back up to her, a little higher than before now that she’s gotten closer.

Absently, you shift in your seat, noticing that you must have lost weight recently. “This Grail War is really taking it out of me, thanks Caster.” You say.

She laughs, lifting your fork idly and using it to mash the potatoes freshly for you. “Here we go… Wouldn’t want you chewing on anything too tough now, would we?” She coos, in a distinctively matronly fashion.

Just then the world seems to jump around you. Everything lurches for a moment, and after it’s passed the forkful she’s holding looks massive.

“Thath too much.” You lisp, blushing. You haven’t lisped since you were a preteen, but something made it come back. Her smile only widens as you clear your throat, embarrassed. “Cathter, pleathe.”

It’s not the first sign that something’s wrong, but it’s the first one you notice. Your eyes widen, and you open your mouth to ask her what’s happening. She pops the mashed potatoes in your mouth before you can muster a question.

“Here comes the train! Silly boy, look at how worried you are. You know, you’re really making me feel great.”

She looks great too, in all honesty. It’s like feeding you is filling her with energy. You had thought the only way to transfer mana so efficiently was through more carnal means, but it seems like this mage is adept enough to bypass that.

“Thankth…” You manage, before pursing your lips. You run your tongue around your treacherous teeth, only to find that they’ve grown as big as they were before you had braces. No doubt that’s the source of your lisp—though you doubt it’s the source of your problems.

She sees you notice her scheme, and the woman lightly flips her hood over her light purple hair. “Well, someone took their time noticing. I was worried that I’d have to actually tell you.”

“Tell me what?”

You panic, looking down to yourself and finding that everything is bigger. “Am I thrinking?” You gasp, watching your shoes slip from your feet. Your shoulders thin enough for your shirt to hang over one of them, and your glasses slip over a too-small ear to hang askance on your face. “Whath goin’ on?”

She doesn’t respond, almost as though she wants you to find out for yourself. You know that Servants are supposed to be rather prideful beings, so you try and humor her by looking at your hands and seeing if there’s anything amiss.

There is indeed. They look different, yet familiar at the same time. That’s the most chilling part about this: you remember looking down to these very hands at least two and a half decades ago. Your heart hammers in your smaller chest, and you feel your lower lip instinctively trembling.

“Am I getting’ youngew?” Your lisp grows more pronounced, thanks to both your regression and to the tears that cloud the corners of your vision.

“Oh, Master… I’m sure that people used to say you were such a smart child. It’s a pity that you were such a naïve adult.” She coos, bringing a too-large hand to stroke at your soft cheek.

You squirm in place, rolling off your chair and falling to the floor—actually falling. You’re smaller enough that there’s a foot between you and the ground, and you stumble for a moment. Then you turn to look up, up at her. She’s twice your height, easily, but you’re not afraid. After all, you have a trump card.

You lift your dominant hand, looking to the Command Seals on your back. They’re supposed to allow you to command your Servant to do anything, and you invoke one with a concentrated thought. “Pweethe change me back!” You say as authoritatively as a child just a few years south of preteen can.

To your displeasure and horror alike, she laughs. “Poor little Master. Don’t worry, I’m going to take such good care of you. After all, you’re just the best little boy there is!” She coos, scooping her hands under your arms and lifting you back onto your seat.

You look to your hand in disbelief, finding that sure enough, the Command Seal was used. Maybe it was a pronunciation thing? You need to say words that won’t make you lisp… You close your eyes, holding your hand above your head. “Make me big again!”

The next rune on your hand vanishes. You can tell from the tingling on the back of your hand. You open your eyes once more with a triumphant smile, only to see her using a spoon to gently mash the peas she’s cooked for you too.

“Does someone wanna grow up big and strong? Don’t worry, Master. A few veggies and you’ll be big as Atlas.” She coos, a hint of her Ancient Greek upbringing creeping into her lexicon. She shoves the spoonful past your lips, and you spit it out with a stomp of your tiny foot.

“Don’ wanna have veggies, wanna big again!” You glower up to her, the effect lessened by the fact that you’re a toddler.

“Oh no… Someone’s throwing a temper tantrum.” She gasps in mock-horror, before a cruel smile spreads across her features. She lifts you once more, this time so she can sit in your chair. Her robed bottom settles neatly on your discarded, too-large clothing, and she bends you over a knee.

You realize then what she’s about to do, and you kick your helpless legs and thrash your weak arms. She’s so much larger and stronger than you that it’s like trying to fight a giant, but you give it all the effort you have.

Then her hand claps against your backside, and a sharp stinging makes you wail with pain. “Stawp!” You screech, going limp instinctively. You look back to her and find her expression is more than a little soft, she actually looks crushed by the fact that she has to spank you.

“Oh, dear… I thought I might enjoy putting you in your place, but I can’t possibly hurt my sweet Master! I suppose I’ll have to spare the rod and spoil the child, won’t I?” She coos. A wave of her hand conjures a cloth diaper about your nethers, and you wriggle in its soft warmth.

“Notaww kidda.” You burble. It’s terrifying to admit, but you’re still getting younger. Frantically, you hop off her lip, falling hard on your hands and knees. You bite your lip to fight back tears, and rise unsteadily to your feet.

They’re too weak, and you’re too clumsy. You manage to toddle a few paces before falling onto your hands and knees.

“How precious. Baby’s last steps.”

You struggle to crawl away from her, but she simply lies down next to you. She’s lowered her hood, and you get the impression that she’s no longer going to be working any more magic on you. Instead, now she’s watching you like a youthful mother would tend for a child.

“That’s my good Master! Yes you are, such a darling baby boy!” She giggles, petting your head before kissing your pudgy belly. Your whole body has more baby fat that muscle at this point, and you jiggle every bit of it when she turns the kiss into a blown raspberry.

“Staa!” You burble, giggling like the infant you’ve become. Even as an adult you were ticklish, and this is so much worse. “Toomaa, gonna-uh oh.”

You know what you’ve done a second before you feel anything, and two seconds before ou smell anything. Caster’s eyes light up at that, and she claps her hands in delight. “What’s that? Did Master make a smelly? Oh, you poor, poor dear! Please, let me change you!”

It’s not like you have much of a choice in the matter. You blush and try and look away, but her contented humming proves to be more of a distraction. You’ve no doubt that she could use magic to clean you, but instead she’s elected to do it by hand.

First, the woman gently wipes your backside with another soft, cushiony cloth. Then she applies just a bit of baby powder—but it’s still enough to make you sneeze softly. Finally, she wraps a new diaper about your bottom and pins it with a proud smile.

“I’ve always wanted to do that! Naturally, I fared impeccably well.” She chuckles, scooping you into her arms once again, this time in a close hug.

“Gaaboo gaa.” You manage, the best that your childlike mind can come up with. You can still think at a relatively unimpeded level, but translating those thoughts to words and actions is the real difficulty. Worse, your body is so naturally happy from all this pampering that you’re beginning to like it.

“Don’t worry, I have you.” Caster purrs. “Mommy Medea is gonna take good care of her big, strong boy.”

Her hug takes on a smooth, rhythmic motion. It’s like the gently listing of a ship, and your eyelids grow heavy. You realize she’s rocking you just as she overdramatically yawns, beaming as you echo the yawn with a genuine one of your own. Then, slowly but surely, your eyelids drift closed and you fall into a restful slumber.