who kidnapped the empress

Well, it could be one of the rivals of the empress or someone with a hidden agenda. Maybe it's related to power struggles or personal vendettas. But it really depends on the specific plot and characters of the manga.

I'm not sure who did it. Maybe it was a rival faction seeking power.

I think it was the evil baron. He wanted to gain power and control over the kingdom by eliminating the empress.

Papyrus can also be a victim of kidnapping in fanfictions. His naive and friendly nature makes him an easy target in some stories. His kidnapping could lead to Sans going on a desperate search for him, which would involve a lot of action and emotional moments as Sans tries to rescue his brother.

The author of 'Kidnapped' is Robert Louis Stevenson.

I have no idea. Maybe it was someone with a grudge against the teacher.

The Naraku would be a likely kidnapper. He is always plotting against Inuyasha and trying to get his hands on the Tessaiga. Kidnapping Inuyasha would be a way for him to either steal the sword or find a way to break Inuyasha's spirit so that he can no longer oppose him.

It could be a new character created specifically for the fanfiction. Maybe a young scientist who is working on a project related to the super - soldier serum. Since Bucky has a history with the serum, this would create an interesting dynamic.

Well, it could go a bunch of ways. Maybe he was rescued safely, or maybe something much worse happened. We don't know for sure without more details.

It could be Alan Breck Stewart. He plays a significant role and shows bravery and determination throughout the story.