Trixie -- Okami Valley

The new person was almost Ellen's height, and even then, she only reached up to her eyes because of her pointed ears. She was dressed in a garishly bright pastel dress, the skirt so fluffy that it did nothing to hide her diaper. The dress's color only stood out more because it clashed with her red and white fur, her face pointed, and a red tail swishing back and forth, its tip white like the end of a used paintbrush.

She was a fox.

"Children, I would like you all to meet your newest classmate, Trixie. Trixie, these are your new dormmates. Say hi, everybody!"

"Hi Trixie," said all of the other babies, some more enthusiastic than the others.

"H-Hi," said Trixie. If her whole body wasn't red, it was likely her face would have been. Her free hand tugged at the end of her skirt, and she looked like she was one move away from nuzzling her face into Ellen's shoulder and pretending all of these strange people weren't here.

Jane made a mental note of how she acted. She had been in the Petting Zoo for a year now, and hearing about the other students at the institute and seeing them all operate the way that they did, she learned a few things. Different worlds had different effects on the regular Joes and Janes (like her) that stumbled into them.

Those under Low Regression were people who were put in diapers and treated like babies because the ones who "adopted" them forced them into it, so it didn't take long to reverse the effects done to them as long as they kept away from whatever world they stumbled into. They could use the potty, but the potty was denied to them whenever it was asked of them, and they were "encouraged" to go in their diapers like good boys and girls. Anyone could get used to anything if it was trained into them.

Moderate regression was a broader spectrum of physical and mental changes that made it harder for them to "grow up" again even if they wanted to. Behavior ranged somewhere from daycare to grade school. They genuinely enjoyed playing with their toys, modesty was a crapshoot, stronger dietary restrictions, and total diaper dependency that could be mitigated with carefully scheduled potty-training that sometimes worked.

High Regression is total infantilization. High Mental Regression rendered them incapable of speech and almost no memory of the person they were. Just fully-grown, brain-damaged men and women crawling on all fours, babbling nonsense, and loving every second of it. High Physical Regression left the "adult" out of the "adult baby" commonality, deaging the worldwalkers unfortunate enough to experience it anywhere between the age of five to that of a newborn.

Like Jane, Trixie was somewhere in the moderate level: She could stand on her feet, she could talk, and she seemed to feel some level of shame. Or more likely, she remembered that a girl her age dressed in baby clothes should have been embarrassed and acted accordingly. Moderately regressed babies liked being babies, at least way more so than Low Regressed ones, but they still remember what it was like to be potty-trained grown-ups who understood that one didn't show off their underwear to a room full of strangers.

After Ellen gave the fox girl a maternal hug and rubbed a reassuring pat on the back, she handed her over to Marie, one of the caretakers looking after all of the Petting Zoo kids in the play areas. Trixie had a fist against her heart, clearly fighting the urge to put a thumb in her mouth for comfort, and she escorted her over to the free pillow next to Jane so that she could properly introduce herself.

Trixie sat on her knees on the pillow, her legs kept apart by her diaper. She had clearly been changed recently, considering how strong the baby perfume was on her.