(Fate/Grand Order TF, F to Femboy, F to Clothing)

“Trick or-” was as far as the Nemo Marines got before the door slammed in their faces. Though they all shared the same face, they each had a uniquely heartbroken look on their faces, all of which stabbed at their chaperone’s heart.

Though the boys might have been soft, Minamoto-no-Raikou was a legendary tiger mom. Rather than knocking on the door, she simply punched a fist through it, dragging it open with a loud squeal of protesting metal.

“The hell are you doing!?” The room’s occupant cursed, withdrawing from the light with a quiet hiss. The gloomy woman was none other than Jeanne Alter, a corrupted version of the French Saint who, at present, wanted nothing to do with any holiday.

“Allowing the dear children to finish.” Raikou’s smile would have been calming were it not for how sharp her words were. Her tone was cold, each word said with the promise to inflict murderous violence onto anyone who disobeyed. No argument would be allowed here.

But, then again, Jeanne Alter never was fond of anyone’s rules. “Sucks to be them, then! I don’t have any damn candy, so pack your crap and get out of my room.”

Raikou’s eyes narrowed. A sword materialized in her hand. Jeanne Alter grinned savagely, summoning her own blade.

“Our room.” One of the Marines called out, forestalling the warriors’ motions.

“Eh?” Jeanne Alter twitched her head towards them, but didn’t break eye contact with Raikou. She was sure that the legendary Japanese warrior was a bigger threat, and was also completely mistaken.

“You are currently aboard the Nautilus, which makes this our divine territory.” One of the other Nemo Marines spoke.

“Sometimes I forget those little creeps share a brain…” Jeanne Alter muttered.

The last Nemo Marine spoke as though “And as such, we have full domain. We control the submarine, its room… And its passengers.”

The first sign that something was wrong was that Raikou seemed to be a little taller, but by then it was much, much too late for Jeanne Alter. The sword in her arms started to feel heavier, and she looked down in surprise to see her clothes sagging around her limbs.

“What the hell!?” Her gauntlets fell loosely from her dwindling hands, and as she raised them, her sleeves dipped down to her elbows. She wasn’t shrinking, she knew that much from how her muscles were rapidly losing their definition. At the same time, it wasn’t like she was somehow aging in reverse—the arms she was looking at were… Different.

It wasn’t that they weren’t feminine, but rather that they were overly so. It was a man’s arm, molded to the slender appearance of a woman’s. Despite being shaved smooth, nothing could hide the supple tone of her new muscles. At the same time, her hands had lost much of their slenderness, now better suited for tools, or rifles. Just like the hands of the costumed Marines.

“No… No freaking way. Freaking? Wait, why can’t I hecking curse!?” Jeanne Alter rounded on the Marines, stumbling from how her boots now reached almost up to her knees. As she shouted at them, her voice deepened slightly, taking on a hint of a masculine bark.

“All Marines are prohibited from profanity, even while on holidays.” If Jeanne didn’t know better, she’d swear the marine was scoffing at her arrogantly. “That includes conscripts.”

“You can’t do this to me, you flying twerps!” Jeanne Alter’s chest ached, and she cut off her tirade to whirl towards the full-body mirror in her room. All of the firmness in her body had lost been lost to the rough-and-tumble boyishness of the Marines. And, from the looks of it, the softness of her form was soon to fade too.

Her shirt and skirt alike deflated, cloth billowing out like an empty parachute. She could feel her generous chest flattening, its fat redistributing to her sides and her once heart-shaped face. The woman’s hourglass figure was soon nothing but a distant memory, replaced with a slim and weak form better suited for scrubbing the decks of the Nautilus.

Which… Was a strange thing to think about. Jeanne Alter lifted one of her hands to her cheeks, wincing in humiliation from the sight of her beautiful hair shortening to match the hairstyle of the other Nemos. “H-hold fiddling on… My head… Nnh…”

“It’s part of becoming our ranks,” one of the Marines marched up to her smartly, patting her on the shoulder. “But don’t worry, we’ll go easy on you.”

“Right!” Another chirped. “No need to haze you when we’re all connected, right?”

Jeanne Alter shrieked as her mind connected with the other Nemo Marines, programming her with the skills needed to run the ship. Of course, even a Servant’s brain could only hold so much, so this new information replaced the old at an alarming rate. She couldn’t even think of herself as an Altered Servant, which meant that the rest of her Spirit Core wasn’t safe either.

“Raikou, you-” Jeanne scrambled for a word that wasn’t there. She was sure it started with a b, but… No, she couldn’t think about that! If she didn’t hurry, she’d even forget she was Neanne! “Miss Raikou, please! Do something!”

“I’m… Not entirely sure I can…” Raikou was conflicted. On the one hand, she should be horrified by the fact that a Heroic Spirit was so reduced before herself. On the other hand, Jeanne Alter was a troublemaker, and the Nemo Marines were such good boys.

“Why would you? It’s another kid to trick-or-treat with, right? And you love keeping us company!” A Nemo Marine beamed.

Neame could see the look in Raikou’s eyes, just like she could feel his brain fading from her head. It was so hard to think of himself as a girl, he was terrified to think about being another servile boy. Even though it felt good to be part of the crew…

She realized he was sharing the same smile as the other Nemos in the room and turned from them with a wail, back her mirror. “No, please, not that! You can’t do this to me, I’m Neamo!”

His reflection moved his lips in time with him, but he could see the light dimming from the reflection’s eyes. “I’m… Uhm… I’m Nemo, right?” He searched for some sort of approval in the mirror, but was only met with confusion.

Then he looked back to the other Marines, finding the approval he was searching for. “A-ah! Many apologies, Nemo Marine reporting for duty!” He saluted, the baggy sleeve of his dress making the motion exaggerated and awkward.

“We’ll have to fix that,” one of his brothers whispered.

The Nemo Marine felt his clothes start to tighten, and he looked down to see them shrinking to match his new body. It might not have been his proper uniform, but it was a perfect Dragon Witch costume for Halloween. He could dress like the rest of the ranks tomorrow, for now he wanted candy.

“Hello?” A new voice called, one that matched the voice the Nemo Marine used to have. Of course, now it was a stranger’s, so it took him a moment to place it.

“Hello? Is there some reason for all the noise?” Jeanne D’Arc herself poked her head around the corner. She looked into her the room curiously, fingers lightly pressing against the crumpled metal of her twin’s door. “Or… The…”

Her voice trailed off as she looked at the newest Marine. Though he only sported the same hair as Jeanne Alter, Jeanne could recognize her sister anywhere.

“Ma’am! Nemo Marine, reporting for duty!” The boy saluted, eyes devoid of any of the rebellion his previous self had sported. His costume, a cheap mockery of his old armor, clanked noisily with the motion. “The reason was because this room’s occupant did not have any candy for us! And she was terribly rude, no offense intended, ma’am!”

Jeanne blinked twice, and when the sight didn’t change, she rubbed at her eyes for good measure. Then she turned to the other woman in the room. “Is… Is this because of Halloween?”

“Very astute!” Raikou beamed. “I am taking the boys around the ship, so that they can experience one of the joys of modern childhood. Oh, my dear Kintoki would have loved this type of holiday. The hauntings to be purged, the candies to be had, the costumes to be worn…”

Jeanne tilted her head to the side, her tiara clinking. “But… You’re not wearing a costume.”

Raikou blinked, then looked to the Marines in shock. “W-wait, should I be? This won’t do! This won’t do at all, I’m so sorry!” The thought of failing as a mother, even for something as inoffensive as this, brought tears to her eyes.

“Ah! I didn’t mean to offend, honestly!” Jeanne lifted her hands palm-out, trying to calm the older woman. “Is there anything I can do to help?”

The newest Nemo Marine nodded. Though no trace of Jeanne Alter’s memories or personality remained, some of her creative instinct must have stuck in his head. “Orders received and understood!”

With that, Jeanne vanished, and Raikou’s outfit was replaced with a skintight leather catsuit. There wasn’t a single moment to process what had happened, much less defend against it. One of Mankind’s most powerful and beloved saints had vanished like a cheap effect from an old movie.

‘Huh? What?’ Jeanne thought, her words unheard by the warm body that was filling her new form. In her life as a saint, she’d never been intimate with anyone, let alone a woman. Now she was molded against another woman’s naked body, trapped feeling the warmth of Raikou’s skin against her cotton lining.

Raikou, for her part, was equally shocked. She cupped her hands against her massive breasts, unknowingly kneading what had once been Jeanne’s face around them. A silver trim around Raikou’s cleavage marked what had once been Jeanne’s tiara. “Where did this come from!?”

Jeanne squealed with a pleasure-tinged shock at the probing touch. Being like this felt so good, it was almost natural. If she wasn’t careful, she might just end up losing herself to this new body. The thought was a chilling one, and she mentally cried out to a deaf audience. ‘N-no, Raikou! Stop! You must take me off at once! I fear what will happen if you do not!’

“Ma’am! That outfit was once Jeanne D’Arc. She volunteered to serve as your Halloween costume, as we all heard.” The pale Marine looked up to the woman, a slight shy blush creeping across his face. “I… I hope you find the design appealing, I produced it myself!”

Jeanne could feel Raikou’s heart skip a beat at that. ‘Oh no… This is bad… I don’t think she was ever given a gift by her children, certainly nothing like this. Please! You must listen! I am not some costume!’

“It looks a little like Miss Koyanskaya’s,” one of the original Nemo Marines whispered.

“Sshh! What matters is she likes it! Besides, if anything it looks like that one witch’s from that game Nemo Engineer showed us.”

Raikou didn’t hear a word they were saying, too enamored with her new present. Ignorant of her outfit’s pleas, she traced her hands down her sides, along the motherly curve of her hips. The leather creaked as she moved.

To Jeanne, the sound was like having her world torn asunder. She followed the feeling of Raikou’s fingers along her new body, mentally quivering at the realization that she was stretched taut by the woman’s full figure.

Jeanne was molded around Raikou’s toned calves, clamped around her thighs, and squished so close to her ass that she could feel every jiggle of her body. No matter how Raikou moved, she’d stretch some part of Jeanne a little more, bringing a little bit more of that mind-numbing pleasure through the transformed woman.

Already Jeanne had forgotten what it was like to wear clothes. Her mental image of herself was completely nude, features flushed with the rush of being worn. ‘Puh-puhleeese… Stoppuh…’ Her mental cries grew slower, more dimwitted. She was rapidly losing the capacity to think, replaced by the pleasure of simply feeling.

“Well, I suppose it is in the season…” Raikou strutted her way towards Jeanne Alter’s mirror, admiring her full figure. “And it seems rather combat-effective as well. Excellent work, I may even wear this more often.”

“Thank you, ma’am!” The Marine beamed, jogging over to the others excitedly. “May we continue trick-or-treating now?”

‘Noooo!!! Jeanne… Uh… Me… Me need taken off…’ Jeanne’s thoughts flickered like a dying flame. ‘Me feel so good but… S’pposed t’be sainty…’

Raikou turned back towards the Marines, subconsciously adjusting her top. Her breasts threatened to spill over Jeanne’s body, so she tucked them in a little more, stretching her outfit further and damning her fellow Heroic Spirit.

‘Puh… Pleeese… Me… Me…’ Were the last thoughts of the catsuit as it crumbled beneath this new wave of pleasure. It had no thoughts, it had no need for them. All it needed was to be worn.

Raikou didn’t know about any of that. As far as she was concerned, she was here to take the young Marines out on a lovely night. “Of course,” she said with a smile. She took the boy’s hand in hers and walked him away from his old life, wearing what had once been his twin.

Unfortunately for Chaldea, and thus the rest of humanity, this was only the beginning of their Halloween night…