How to deal with Hiccup being kidnapped by Viggo in How to Train Your Dragon fanfiction?

First, you could have the other characters in the story come up with a rescue plan. They might use their skills and knowledge to track down where Hiccup is being held and figure out how to get in safely.

First, you need to have a clear idea of their characters and the setting. Then, think of an interesting plot that could involve both Hiccup and Viggo. Maybe start with a conflict or a mystery for them to solve together.

First off, you might introduce a wise healer character who knows the remedy. Or, you could have Hiccup's friends embark on a dangerous quest to find the cure. Another option is to have Hiccup's inner strength and determination help him fight off the poison gradually.

Maybe Hiccup could learn some self-defense skills and stand up for himself. Or, he could find an adult he trusts to help him solve the problem. It all depends on how the story unfolds and what kind of tone you want to set.

Well, you might consider having other characters give him warm clothing or blankets. Or perhaps he could use his inventing skills to create a device that generates heat. Maybe there's a hot spring nearby that he finds and takes advantage of.

You could have other characters try to wake him up with various methods, like using magic or seeking help from a wise elder.

You might make the illness a metaphor for a larger challenge Hiccup needs to overcome within himself. It could lead to personal growth and a deeper understanding of his role in the dragon world.

One way could be to introduce a magical cure or an event that breaks the brainwashing. Maybe a key moment from Hiccup's past triggers his return to normal. Also, the support of his dragon could play a crucial role in restoring his mind.

One way could be to have him get some much-needed rest and recovery time. Maybe he takes a nap or spends a day doing nothing but relaxing.

Well, it varies a lot in fanfiction. Sometimes Hiccup and Viggo become unlikely friends, while in others, they remain bitter enemies. The plot depends on the author's imagination and creativity.