[Diapered Avenger]

Erza Scarlet was traversing the ruins of an ancient temple in search of a powerful armor she thought would be great in combat. After some searching, she found the rumored armor in question. When she requipped it to try it on, there was a bright flash that knocked her out cold.

When she woke up, she was back in her room, in her bed. "What... just happened?" She asked herself. Erza then noticed something felt strange. She looked underneath her covers and gasped. Instead of her regular panties, Erza was wearing a bright, pink diaper with unicorn designs. "What the hell?"

.....

After a long S-Rank mission, Ultear was given enough time off for two weeks. Naturally, she wasn't sure what to do, so she decided to relax at a local cafe to think of ideas. While enjoying her coffee, she noticed a mother was playing with her child. She had no idea why, but was entranced by the sight. It actually made her wish she had something like that.

So Ultear went home and started to do some research on potentially looking into childcare, or taking a few jobs that allowed her to help out children. While she saw some pictures of babies in cute outfits, she jokingly wondered what an adult would look like in clothing like that. And that was when she looked up the term "adult baby."