Who could be the main antagonist in 'anakin saves the younglings fanfiction'?

In this fanfiction, it might be that Anakin has a vision of the future where the younglings grow up to be great Jedi and save the galaxy. So, he defies Palpatine's orders. He could enlist the help of some loyal clones or other Jedi who have managed to escape the initial purge. He then takes the younglings to a remote planet where they can be safe and trained in secret.

It could be a rogue ninja from Tobirama's time who has a vendetta against the Senju clan. This ninja might have been waiting for the perfect moment to strike at Tobirama when he is alone or vulnerable. Naruto then has to face this powerful and vengeful enemy to save Tobirama.

It could be a rogue ninja who is using the poochyena for some sort of evil experiment. Naruto has to stop this ninja from harming the poochyena.

Perhaps a new and original antagonist could be created for this fanfiction. This antagonist could be a rogue ninja who has mastered a forbidden jutsu that allows him to manipulate time as well. He could be the one who sets up the events that lead to Minato's endangerment, and Naruto has to figure out his motives and stop him while also saving Minato.

Perhaps it's a group of mercenary ninjas. They've been hired by someone who has a grudge against Zabuza. They see Zabuza as an easy target when he's alone or vulnerable, but Naruto shows up to spoil their plan.

The main antagonist could actually be Anakin's own self - doubt. Since he's in a child's body but has an adult's memories, he might struggle with feelings of inadequacy. This internal struggle could act as an antagonist, preventing him from fully embracing his new situation and using his abilities to the fullest. It could be a psychological battle within himself that holds him back more than any external foe.

A Sith Lord who has been manipulating events from the shadows could be the antagonist. This Sith Lord might be trying to use Rey's connection to Anakin to bring about the return of the Sith in a new and more powerful way. He could be using dark side illusions to make Rey and Anakin distrust each other.

It could be a dark wizard who has a vendetta against goblins. This wizard might see goblins as a source of power or wealth and wants to enslave them. So when Harry tries to save the goblin, this dark wizard becomes the main obstacle.

Maybe an old enemy of Madara who realizes that by targeting Naruto, he can get back at Madara. Since Madara has some sort of connection or interest in saving Naruto in this fanfiction, the enemy thinks that if he can harm Naruto, he can either draw Madara out or simply cause him pain. This enemy could be a powerful rogue ninja with a vendetta against Madara.

It could be a new villain who has a grudge against the Justice League. Maybe someone whose family was affected by the League's actions in the past. This villain would be very smart and powerful, creating elaborate traps for the League members.