Who could be the main antagonist in 'ash turns into a mew fanfiction'?

Team Rocket could be the main antagonists. They might see Ash's transformation into Mew as a way to capture a powerful Pokémon - like being. They could devise all sorts of plans to catch him, thinking that they can use Mew - Ash's powers for their own evil purposes.

A powerful and greedy Pokémon collector could be the main antagonist. He wants to capture Ash, now in his Mew form, to add to his collection. He has all sorts of high - tech devices and trained Pokémon to try and catch Ash.

Team Rocket could be the main antagonists. They might hear about Ash's encounter with Mew and try to capture Mew for their own evil plans. They could set up all sorts of traps and schemes to try and separate Ash from Mew and steal Mew away.

Maybe Team Rocket could be the main antagonist. They might see Ash's transformation as an opportunity to finally capture Pikachu. Since Ash is in a more vulnerable state as a girl, they could try to use different tactics to take advantage of the situation.

Perhaps a jealous trainer. This trainer has always been envious of Ash's success and now that Ash is in a vulnerable state as a Zorua, the trainer sees an opportunity to get rid of him for good. The trainer could try to use his own Pokémon to capture Ash or even harm him, making the trainer a formidable antagonist in the story.

Perhaps a dark - type Pokémon that is jealous of Ash's new form. This Pokémon might see Ash as a threat and constantly try to attack him and stop him from getting used to his Latios form.

It could be a Team Rocket member who has obtained a new device. This device was meant to transform Pokemon into other forms for their evil purposes. But by accident, it affects Ash instead. So, this Team Rocket member becomes the main antagonist as he tries to either capture Ash in his new Glaceon form or use him for other devious plans.

It could be a jealous trainer. This trainer might see Ash in his shiny pokemon form and want that power for himself. So he tries to capture Ash by any means necessary, setting up all kinds of traps and challenges for Ash and his friends.

Maybe a powerful and evil pokemon trainer who has a vendetta against Ash. Now that Ash is in a vulnerable pokemon form, this trainer could try to capture and control him. The trainer might have some dark motives related to using Ash's unique situation to gain power in the pokemon world.

A jealous male trainer could be the main antagonist. He might see Ash's transformation as an unfair advantage given by some mysterious power. He constantly tries to undermine her in battles and challenges, believing that a female should not be as successful as a male in the Pokemon world.