Who could be the main antagonist in a 'Fairy Tail Lucy becomes a Dragon Slayer' fanfic?

In a 'Fairy Tail Lucy becomes a Dragon Slayer' fanfic, it could start with Lucy being in a life - threatening situation. To survive, she unknowingly absorbs the power of a dying dragon. This power starts to change her. At first, she is scared of the changes. But then, with the support of her friends, she decides to embrace it. She then begins a journey to master her new powers. She might learn that her Dragon Slayer magic is linked to a special type of celestial spirit that has dragon - like qualities, and she has to find and bond with this spirit to fully control her powers.

Perhaps an ancient sorcerer who has the ability to control celestial dragons. He sees Lucy as an obstacle to his domination over the world using the power of these dragons. He would use his vast knowledge of magic and his control over the dragons to try and defeat her.

It could be a rogue dragon slayer who has turned to the dark side. This slayer might be jealous of the power and camaraderie in Fairy Tail and wants to destroy it. They could use their dragon slayer powers in cruel and unusual ways, causing chaos wherever they go.

It could be a dark wizard who wants to steal the power of the Hellfire Dragon Slayer. This wizard might be from a long - lost cult that once worshipped the dragons but now wants to use their power for evil. They could see the slayer as a key to unlocking some ancient and dangerous magic.

Well, if we consider Lucy as a Dragon Slayer in fanfiction, her magic could be really different from the traditional ones. Maybe she'd have a connection to a celestial dragon, which would be so cool. It would combine her existing celestial spirit magic with the new dragon slayer powers. She could use the stars as a source of power, similar to how other dragon slayers use elements, and it would be a fresh take on her character.

A powerful and evil dragon could be the main antagonist. This dragon might have a grudge against the dragon slayers in general and specifically targets Lucy because of her growing reputation as a star dragon slayer.

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.

It could also be a group within the Fairy Tail guild itself. Some members might be jealous of the 5th generation dragon slayer's power and potential. They form a secret faction that tries to undermine the dragon slayer at every turn, from spreading false rumors to sabotaging their missions. This internal conflict would add an interesting layer to the fanfiction as the dragon slayer has to deal with enemies both inside and outside the guild.

A powerful dark wizard who wants to steal the Phoenix Slayer's power for himself could be a great antagonist. He could have an army of dark creatures at his command and constantly be devising plans to defeat the Phoenix Slayer and take over the magical world.