“All done! Finally!” Marin almost cheered in relief as she slammed her pencil down onto her desk and snapped her book shut, her homework completed on time for once. It had taken some extreme arm-wringing from Gojou to do it, but she had gotten her homework complete and had a fresh slate for the rest of the evening, which meant it was time for… Marin’s eyes lit up as she grabbed her phone and went straight to the transformation app she had installed the previous night, giggling to herself as she went over her potential options from the list. So many choices, so little time!

After her surprising transformation last night, things had mostly settled down. She made Gojou freak out when he arrived and was met by an obese floating Marin with a giant mouth where her navel should have been, but after he calmed down and the situation was explained, he took it rather well. And by took it rather well, he only looked a little traumatised when he finally left the next morning. He’d cooked for her as she demanded, and after the six hours were up, she had fallen onto her bed from where she was floating and showing off, landing fully clothed and as skinny as ever. It was kind of weird readjusting to having only one mouth, though. After being convinced that the app was harmless, Gojou had, in a moment of clarity, realised that her grades were about to drop through the floor with that kind of thing as a distraction, and forced her with an icy chill in her voice that he would confiscate her phone and delete the app if she didn’t finish her homework before using it again. However magical the experience might be, she still had a life outside of it.

After reluctantly agreeing, she had been compelled to work hard for once, and now found herself with plenty of free time. Unfortunately, the shortest she could transform herself for was six hours, so she could only try one other form tonight. And the one she settled on, after a lot of umming and aahing was… An oni! Transforming into something bizarre was one thing, but an oni appealed to her cosplayer’s sense. Red or blue skinned, horned, and otherwise normal, she figured she could pass it off as just a very convincing cosplay this time. Plus, it simply made sense to go from fat to fit. And so, without any hesitation, she lined herself up in front of her mirror, cheerfully selected it, and let it begin.

The first thing Marin noticed was her clothes vanishing the moment she pressed the button, nodding in agreement at her reflection at how appropriately oni-like her outfit was. A tiger-print bikini, a loincloth, and nothing else! If it stopped here, she probably could have fished out a green wig and makeup and called it an impromptu Lum cosplay. Then again, it wasn’t too different from the swimsuit she already had. She waited patiently for the next step, an uncontrollable grin on her face as she lifted herself up and down on the balls of her feet, her bikini-clad boobs bouncing slightly. Marin had been expecting her skin colour to change next, and didn’t notice that each time she returned to flat feet her head was up a little higher, her legs a little longer. After ten bounces, her head started to clear the top of the mirror’s frame, and Marin finally noticed her growth. She looked down and around the room, gawking at how far away the ground was and how small things to be. How big was she by the time she stopped growing? It had to have been bigger than Gojou, maybe a head taller, dwarfing her original body.

Next, Marin noticed her usually soft body start to harden, her smooth but ever so slightly plush belly becoming toned, then gaining visible muscle definition, as if she had jumped forward in time to after spending months at the gym. It hardened and defined again, going from toned to washboard, a chiselled six-pack that, while powerful, wasn’t too thick for her tastes. The rest of her body followed this trend, Marin holding out her arm and flexing as she watched it go from thin and girly to thick and buly, her bicep growing large, but without the drooping that had come with her previously fat transformation. This looked like it was carved from granite, hard to the touch. It reminded her of muscular anime women she had seen: hulking but still feminine, like she could bench press a car without looking like Mr. Universe. She watched her shoulders firm up then focused on her legs, which had gone from looking like a place for a delightful pillowy nap to looking like she could crush a watermelon between them without even trying. There was a certain rugged quality to her that fit her amazoness look, but Marin did still look like a human, just one who was a very tall bodybuilder. However, just because she had lost nearly all of her body fat didn’t mean that her curves suffered. She had broad hips and those thick thighs were alluring enough for a man to want to die between, and her breasts were firm and perky as they swelled up, almost the size of her head as they grew to keep up with her enlarged proportions.

“It’s here!” Marin said excitedly in a deeper, huskier voice as her skin started to darken and turn red, and she pushed her bangs aside as a lump formed on her forehead, a spike pushing itself directly outward until it stood several inches long, an unmistakable sign of an oni. Her toothy grin became toothier, her teeth growing pointy and almost razor sharp, her canines enlarging until they stuck out far enough to become tusks, her bottom canines sticking out of her mouth and pressing against her upper lip even when her mouth was closed.

“This is perfect! I totally look just like an oni!” Marin said, her giggly tone unbefitting of how low and deep it was. Nor was it befitting of her to skip around like the schoolgirl she was, posing in the mirror and being unable to hold a menacing tough-girl glare for more than a few seconds before laughing at how serious she looked.

“This is seriously the best! I’ve gotta get some photos!” Marin laughed, stepping back towards her phone, feeling like she could cover her whole room in one step with her long legs. However, she had only taken a couple of steps before something felt off. Something rubbing between her legs, brushing against her loincloth. Something long, dangly, and kind of sensitive. What could it possibly be? Marin’s hands innocently strayed to under her loincloth, where her hands met the mystery. If it was possible for a red-skinned oni to go pale, it happened then and there. She slowly looked down, lifted her loincloth, then dropped it again. Marin started sweating, suddenly glad she hadn’t invited anybody over to show off the app. Since when did becoming an oni mean you suddenly grew a penis!?

Marin fondled her newfound member, unsure of how she was supposed to handle it. It was so weird and long and floppy! When she moved, it wobbled around and felt strange! Not bad, but strange! How was she supposed to get around with this thing! It was so distracting! And to make matters worse, it was going from floppy to hard the more she touched it! Marin wasn’t so naive to not know what a penis looked like, not with the amount of hentai she consumed on a regular basis, but she certainly hadn’t ever expected one to be on her! Was this how Gojou felt all of the time?

“It’s getting bigeeeerrrr!” She wailed as continuing to touch it proved to be a bad move, stumbling around the room even redder in the face as she tried to get her new member to calm down. Then, she paused.

“Isn’t there supposed to be, you know, the other thing?” She wondered aloud, but found no balls to go alone with her manly appendage. In fact, her feminine features were still there as well! She had the best of both worlds! The word “futanari” came to mind, which made it a little easier to cope with, somehow. Still, she couldn’t help but complain as she realised the real problem with sudden. “This stupid thing is totally gonna ruin my photos!”



Marin looked at the mirror, dismayed at the intrusive appendage, wishing it would just calm down and stop tenting through her loincloth! She sat down on the end of her bed with it awkwardly sandwiched between her thighs, hoping it would soften on its own. To pass the time, she decided to look up some cosplayers she liked who had done oni cosplays before, figuring she could take some inspiration from them on posing and how to take a good selfie. To her mortification, whatever angle she presented herself from, as long as her lower half was in it,

“Shiki’s such a good cosplayer…” Marin sighed as she looked over one of her idols, covered in blue body-paint and flexing despite being thin as a stick and five-foot-nothing. It was more the image that mattered, right? Besides, Marin could easily forgive her, since she was so pretty, and beautiful,and hot, and sexy, attractive, and hot, and…

Marin pulled over. She knew Shiki was pretty, but she hadn’t had this strong of a reaction to her before. Right now when she looked at her, she wanted to just eat her up! She tried to forget it by checking other cosplayers, but all of the women were way sexier than she remembered! The culprit for this change in perception revealed itself when she noticed just how rock hard her cock was, Marin realising just how much worse she had made her problem.

“Gojou, Shiki, I’m soooo sorry!” She apologised for her own lewd mind for once as she rushed to her bathroom to satisfy herself where she wouldn’t make a mess…