Who could be the main antagonist in 'natsu fire and ice dragon slayer fanfiction'?

It could be an evil ice dragon that has gone mad with power. This dragon might be hoarding all the ice magic in the land, causing problems for the people and other magical creatures. Lucy would then have to face this powerful foe to restore balance.

A powerful dark mage who wants to use Lucy's newfound dragon slayer powers for his own evil purposes. He might try to control her or steal her powers.

Perhaps an evil mage who has been researching on how to control dragons. When he hears about Natsu's transformation, he sees Natsu as a perfect specimen to experiment on. So he becomes the main antagonist, trying to capture Natsu and use his powers for his own dark purposes.

It could be an evil dragon slayer who is jealous of Natsu's new form. This antagonist might try to steal Natsu's power or find a way to turn him back to his normal self out of envy.

A powerful dragon - themed pirate could be the main antagonist. This pirate has a crew of dragon - like creatures and they are causing chaos across the seas. They have a grudge against Luffy for some reason, perhaps because Luffy has unknowingly entered their territory or stolen something valuable from them.

A powerful dark dragon that was once sealed away but has now broken free. It could have a vendetta against all dragon slayers, especially Gray.

A young orphan who has been training to be an ice dragon slayer since a young age. They have a strong will to prove themselves in a world that has always looked down on them because of their lack of family and resources.

Maybe an ancient dragon that has been awakened from its slumber and views Natsu as an intruder in the dragon world. Since Natsu is a new - made dragon, this old dragon might try to drive him out or even harm him.

A great plot could be about Natsu and the ice dragon slayer (let's say a new character) teaming up to defeat a powerful dark wizard. They have to overcome their differences in magic types and personalities at first. Maybe the ice dragon slayer has a cold and reserved nature compared to Natsu's hot - headedness. As they fight together, they learn from each other and create new combined attacks. For example, Natsu could use his fire to heat up the air around the ice dragon slayer's ice attacks, making them more powerful and unpredictable.

It could be another powerful mage who is jealous of Natsu's new war god slayer magic and wants to steal it for himself. This mage might have been researching ways to gain such powerful magic for a long time and sees Natsu as an obstacle to his own plans.