Who could be the main antagonist in 'hiccup turns into a dragon fanfiction'?

A rogue dragon rider who has different ideas about how to treat dragons. He might see them as tools for power rather than friends like Hiccup does. This rider could be causing trouble for Hiccup and his tribe by stealing dragons or using them to attack other tribes.

A power - hungry Viking who sees Hiccup's transformation as a threat to his own authority could be the main antagonist. He might try to capture Hiccup in his Night Fury form and use him for his own evil purposes, like trying to create an army of transformed creatures.

Perhaps an ancient dragon that has been sleeping for centuries and wakes up to find Astrid turning into a dragon. This dragon sees Astrid as an abomination because she was not born a dragon but is becoming one through some unnatural means. So, it decides to hunt her down and destroy her.

Perhaps a jealous wizard. He was once friends with Astrid but when he sees her gain the power and beauty of a dragon, he becomes envious. He starts to cast spells to make Astrid's life as a dragon difficult and tries to steal her new - found powers for himself.

A powerful dragon rider from a far - off land who has a grudge against the Berk tribe (Hiccup's tribe) could be the main antagonist. He or she sees Hiccup and Heather's marriage as a symbol of the growing strength of Berk and decides to target them specifically to weaken the tribe. They might try to steal their dragons or spread false rumors about their marriage to create unrest among the people.

One possible plot could be that Hiccup's transformation into a baby dragon is the result of a magic spell gone wrong. He then has to figure out how to reverse it while experiencing the world from a dragon's perspective. He might make new dragon friends who help him understand his new form and search for a cure.

It could be an ancient dark wizard who has been manipulating events from the shadows. This wizard might see Elsword as a powerful tool and has been slowly influencing him to turn dark. The wizard could be using dark magic to cloud Elsword's mind and make him more susceptible to negative emotions.

Bowser could be the main antagonist. He might see Luigi's transformation as an opportunity to mess with Mario and the Mushroom Kingdom. He could try to use Luigi's new form to his advantage, perhaps by trying to make Luigi a spy or by using his new identity to cause chaos among the kingdom's residents.

Perhaps an evil mage who actually intended for the transformation to go wrong on purpose. They might want to use Sans' new female form to cause chaos in the Underground. They could be trying to manipulate Sans into doing bad things or using her to get to other important characters.

It could be a jealous rival. Maybe someone who has always been envious of Robin's abilities or popularity. Now that Robin is in a more vulnerable state as a girl, this rival sees an opportunity to undermine him.