A Different Partner for Ladybug
 

If you asked Kagami Tsurugi if she was a superhero, she would tell you those aren't real until today. Now, there were actually magical supervillains attacking the city of Paris she was just starting to call her home, and this magic jewel called a Miraculous could give her powers. Using the white necklace, Kagami transformed into a swan-themed outfit... that looked more infantile than she expected it to.

a small swan appeared next to her. Hello there little bird I am here to help you with becoming a great super hero to the defend Paris

"How can I transform? And what's your name?"

It's a different case for you. You will have use the jewel and ask for your baby costume and I will transform your. My name is Luna sweetie pie

"It's a pleasure to meet you, Luna--" Kagami stopped as she heard what she said. "I'm sorry, did you say 'baby costume'?"

Yeah see your going to be the new hero baby bird and your strength comes from being a embarrassed baby girl.

Kagami's eyes widened. "What kind of superpower is that?!"

You get the power to fly as well as super strength just with the downside of incontinence but everything else is a plus

"Incontin--I have to wear diapers too?" Kagami tried to take off the necklace.

I'm sorry but it's too late to get rid of the necklace sorry but at least you are adorable. She started to use her powers to turn her panties into a huge diaper