Who could be the main antagonist in a 'Grease 2' Michael OC fanfic?

Perhaps the OC is an exchange student from another country. Michael is immediately intrigued by this new and different person. The OC brings a whole new perspective to the school and the greaser gang. They introduce new music and dance styles, which at first are met with some resistance but then are embraced. As the OC and Michael grow closer, they have to deal with the jealousy of other characters and also find a way to blend their two different cultures into a unique and exciting sub - culture within the school.

A new, original villain created just for this fanfic could be the main antagonist. This villain could be a powerful sorcerer who has been observing the Avengers from the shadows. When the OC is reborn, they sense a disruption in the magical balance of the world. Believing the OC to be a threat to their own plans of ruling the world through magic, they set out to eliminate the OC and in the process, come into conflict with the Avengers.

It could be a powerful Arrancar. In the Bleach universe, Arrancars are often antagonists. A particularly strong and cunning one might see the oc as a threat to their plans. Maybe the oc's presence disrupts the Arrancar's scheme to take over a certain part of the Soul Society or gain more power.

Maybe the main antagonist is an agent of the World Government who is secretly operating in the West Blue. They view Shinshi's activities, whether they are innocent or not, as a potential disruption to their plans in the area. So they try to stop Shinshi by any means necessary, setting up various traps and sending assassins after him.

Perhaps an existing 'One Piece' character could be turned into the main antagonist in the context of this fanfic. For instance, a marine officer who sees the OC as a threat to the world government's order. Since Viola has ties to Dressrosa, which has its own complex relationship with the world government, this marine could target them both. The officer might use underhanded tactics to try and stop the OC and Viola from achieving their goals.

A powerful dark mage who was once a member of Fairy Tail but was banished for using forbidden magic. This mage now wants revenge on the guild and sees the reborn OC as a threat to his plans. He has the ability to control shadows and can create illusions to deceive the members of Fairy Tail.

It could be a Rebel spy within the Empire. This spy would be constantly trying to undermine the OC's progress and expose their true intentions. The spy might see the OC as a threat to the Rebellion's plans, especially if the OC is rising in the ranks quickly.

A human hunter could be the main antagonist. He has a grudge against all kung fu animals, especially wolves. He believes they are too powerful and dangerous. He hunts them down one by one and when he hears about the wolf OC in the Valley of Peace, he sets his sights on the valley, causing chaos and danger for all the inhabitants, including the wolf OC and his new friends.

Perhaps a corrupt law enforcement officer. He doesn't want Jake to get too close to Michael Myers because he has his own secrets related to Michael's past killings. He tries to stop Jake from uncovering the truth and ends up being a major obstacle for both Jake and Michael.

Perhaps a group of anti - technology extremists could be the main antagonists in an Ultron fanfic. They see Ultron as the symbol of all that is wrong with technology and are determined to take him down, no matter the cost. They might use their own advanced, but more rudimentary, technology to fight against Ultron. This would create an interesting contrast between Ultron's high - tech abilities and their more basic, yet effective, methods.