[ABDL, Daddydom, Mental Regression, Diaper Use, Soiling]

Thanks to the tireless efforts of the Phantom Thieves of Hearts, many parts of the conspiracy that lurked beneath the shadows had been undone. However, to tackle the last few steps, they needed to be at their utmost peak.

For this reason, the young Okumura Haru, otherwise known as Noir when in her disguise, was currently spending time in the middle of Mementos to train herself to that peak. She had only just joined the group a little while ago, but she wanted to catch up and prove that she wouldn’t be a burden! Sure, she couldn’t quite put in as much strength as the rest, and she was a little clumsy thanks to the lack of training, but all of that could be overcome with sheer grit and determination!

“Goodness me, they just keep coming…” The fluffy-haired girl said aloud as she wiped her brow slightly, watching an onslaught of shadows creeping towards her without hesitation. She needed to deal with them now rather than later, so she could catch her breath and recover from the last few fights.

As Haru raised her axe to plow through the common crowds, she didn’t realize that one of the shadows that had been drawn towards her was merely watching from the sidelines, keeping a close eye on everything she did. It was almost unnatural and eerie, and she didn’t even notice as it crept closer, inching towards her tender form with a leer in its eyes…

The newest Phantom Thief lifted her axe up once more as she hoisted it over her shoulder, slightly sighing as she felt her muscles aching. She had been at this for hours now, surely she could take a break? “I say, if this is what Joker and the rest get up to on their days off, no wonder they were able to…” She began to mutter and hypothesize, not realizing that another enemy was looming over her…

She only felt danger encroaching when it was far too late, as she felt a hand touching her shoulder. “Excuse me.” A deep and rough voice echoed through the young lady’s voice, prompting her to jump forward in surprise while swiveling around to face the enemy. “You’re a pretty young thing, what are you doing in this place?” He asked once more, while she took a second to give him a thorough scan.

It… It looked like an ordinary human man, though one that looked just a little too offputting? He wasn’t wearing anything except for a pair of boxers that seemed to be dirty, not to mention his body wasn’t in the best of shapes with his belly hanging out over the waistband of his underwear. Was he a shadow? He seemed just humane enough that he felt unnatural, but the presence he gave off was far too foreboding to make him anything but a monster…

“Are you afraid?” The fatherly figure asked as he approached her once more, with not a single piece of malice in his eyes. “Young girls like you are so tightly strung up these days, I just want to know if you’re alright. You were breathing raggedly when I saw you…” He continued, the words sounding supportive, but his attire didn’t make him convincing in the slightest…

Haru had to do something to keep him away. “Stay back!” She cried out as she called forth her Persona, casting a quick spell to try and disuade him from approaching without her permission. If she was lucky, he’d back off after that. If he kept on approaching, she’d just have to break out the bigger guns…

Unfortunately for her, it just seemed to plink off him as if he was completely immune to the blow. “Oh, you’re afraid. That’s okay. Daddy won’t harm you. Here, I’ll show you.” The creature wearing a human form smiled as he extended his hand, only for a foul looking substance to shoot forth at her, almost as if he was casting his own spell on her.

She didn’t have a chance to dodge, as she quickly raised her axe to try and defend herself. A futile effort as the spell just passed through her. It didn’t hurt either, and merely made her feel a little sick. She sneezed and stumbled backward, tripping as she felt as if she had been shifted off balance. Upon landing on the floor, she became deadly aware of what it had done to her.

The young Phantom Thief wasn’t wearing her usual outfit any longer, far from it. She was back in her usual sweater, the outfit she wore on a day to day basis. But on top of that, she wore something surprising and ultimately humiliating between her thighs, something that she would’ve never dreamt of wearing without an express need for it. She wouldn’t be caught alive wearing something that infantile…

Poor Haru was diapered, and there was no way for her to hide it. It was simply way too big to cover up, and even if she tried, she had a feeling that she couldn’t keep it up. It squished and crinkled between her thighs, and it made her butt look even bigger than it had, making the would-be-thief shiver and worry. Had she been disarmed? No, she.. She must still have access to her abilities, her axe hadn’t disappeared yet!

She tried to summon her Persona once more, but all she got for her troubles was a thumb in her mouth stopping her chant. “E-Eh…” She mumbled around the digit, a bit of drool running down her chin uncontrollably. Why was she doing any of this, and more importantly, why did it feel natural?

If she had bothered to bring an ally, she might’ve realized that she had just been hit by a special Status Effect, changing her overall role in the party from anything useful to the utterly useless and adorable [Daddy’s Girl], which came with a complementary pair of pampers that was sure to keep her safe and snug in any situation.

“That’s more like it, you look much better like this, my little Baby Girl.” The monster in the form of a human chimed as he crept closer, smiling as he reached out with his hand. “Here, you can stand back up on your little legs, can’t you dear?” He chimed, feeling a sense of pride over seeing ‘his girl’ like this…

Haru wanted to speak up, but she couldn’t force out a single word due to a combination of the thumb and the spell’s effect on her mind. In fact, as she reached out towards the hand that had been offered to her, something in the back of her mind was screaming at her to try and make her stop. It could be even more dangerous..!

She put her hand in the monster’s hand, and another shock pulsated through her body. She had just been hit by another spell, further powering up the status effect that had turned her into [Daddy’s Girl]. The thumb in her mouth left it for a brief moment, only to be replaced with a tough and rubbery pacifier that she couldn’t possibly pull out herself. And it was only one part of her changes…

Next came those silly clothes of hers. While she was normally comfortable in her sweater, when it was combined with the diaper between her legs it stood out and caused her to shiver and blush like a little girl. Not to worry, Daddy had something much better in mind for her. That sweater of hers quickly spread out across the rest of her body, growing in thickness and taking on a deeper pink shade, until it had transformed all the way into a onesie with a cute hoodie for her to wear and hide her head in.

Combine all of that with her axe having been turned into a giant rattle, and it was painfully obvious that she had been further turned into [Daddy’s Baby Girl]. “W-Why are you doing this..?” She tried to mumble out through the thumb in her mouth, but most of it was slurred up by her spit, and it didn’t look like Daddy cared even when she did manage to get a proper word out…

The larger man, who definitely had to be some sort of Shadow or Monster given the way he treated her, just reached around her and lifted her into his arms. “Look at you, my little Baby Girl. You’re so afraid, I can see it in those big eyes of yours. I think we should just take you home, before you get hurt. Good girls like you can’t defend themselves without their Daddy.” He laughed a little, with every word fully intended to grind away at her will to disobey, since his words were as honest as he felt they could be. And since she was his Baby Girl, then she had to think he was right…

“Hurt…” Haru muttered as she pulled the thumb out of her mouth, only for a pacifier to quickly replace it thanks to the status effect put on her. Not only that, but since her hands were uncovered, a pair of mittens and booties appeared on her hands and feet respectively, leaving her looking even more adorable in her deep pastel pink onesie, even as the diaper bulged out through it thanks to how big it was. “Dun wanna hurt…” She muttered out through the rubber in her mouth.

Daddy smiled and gently caressed her head, ruffling her hair in the process. “Exactly. My little Baby Girl shouldn’t get hurt.” He affirmed, casting one final dose of his malicious status effect on the Phantom Thief, intending to finish her off then and there to ensure that she would remain his beautiful and cute little Baby Girl.

The little girl’s eyes blinked and fluttered as they slowly grew empty. She could feel something slipping away from her, but she didn’t exactly understand what it was. What was she losing? Was it… something important? Was it who she was? What was her name, even?

She groaned and whined as she started squirming in Daddy’s arms, while her stomach had begun rumbling. She wasn’t aware of it at all, but all the important thoughts in her head like who she was, where she was, what she should be doing and things that adults would worry about, all of that was gathering in her tummy in the form of a big stinky knot that needed to leave her body as soon as possible. And what did babies do when they needed to get rid of something that was causing them tummy troubles?

They did the only thing they could do! Push until it got out and stopped bothering them! Push, push push and push! The little baby’s eyes shut as she put as much pressure on her butt as her little empty brain possibly could, right up until she could feel the knot in her tummy going away.

As soon as that knot went away, she could feel her butt growing warmer, and a certain smell wafting its way into her face. She whined a little as she tried squishing her thighs together, only to feel the mushy mess resting in the back of her stinky diaper. She had pooped herself, and she was still in the middle of it too, because the back was sagging beneath Daddy’s elbows…

“Hohoho, looks like my little Baby’s making big poopies! Aren’t you the cutest little thing?” The Shadow-y Daddy chimed as he slowly walked into the darkness that surrounded them, rubbing away at her stinky bottom as he cooed. “You’re going to grow up to be such a good girl, aren’t you? My little poopy angel…” He continued heaping compliments onto the regressed girl in his arms, even as she started idly drooling thanks to how much of her mind she had pooped into her pampers…

It wasn’t her fault. She couldn’t be blamed, she was nothing more than [Daddy’s Stinky Baby]. She couldn’t make thinkies, but she could sure make stinkies when she wanted. And then Daddy would give her a change, because that’s what she deserved. She didn’t know that she had once been a thief, or even that she was once named Haru.

All she knew, was that she loved her Daddy. And love him, she very much did.