Who could be the main antagonist in a 'Harry Potter Controls Metal' fanfiction?

It could be a dark wizard who also wants to control the zombies but for evil purposes. Maybe a long - lost relative of Voldemort who has emerged from the shadows and sees the zombies as a means to finally take over the wizarding world. He might try to steal Harry's method of controlling them or create more powerful zombies that are immune to Harry's control.

Maybe Harry discovers a new spell that allows him to control metal. He could use this power to defend Hogwarts. For example, he might be able to manipulate the metal gates to keep out dark wizards.

It could be Orochimaru. He's always been interested in new and powerful jutsus. He might see Naruto's shadow - controlling ability as something he wants to steal or use for his own evil purposes.

It could be a rogue Huntsman who wants to use Ruby's power to control Grimm for his own evil purposes. He might believe that with the Grimm under his control, he can rule over Remnant. He would then be constantly trying to kidnap Ruby or figure out the secret behind her power, and would oppose team RWBY at every turn.

A powerful dark spirit might be the main antagonist. This spirit could sense Naruto's new ability to control darkness and see him as a threat. So it starts causing chaos in the ninja world, forcing Naruto to use his dark - controlling powers to stop it. The spirit could have the ability to possess other ninjas, making them do its bidding.

It could be another character who also has some time - related powers but uses them for evil. This character might try to steal Percy's time - controlling ability or use their own powers to disrupt the timeline for their own gain.

There could be a powerful shinobi from within Konoha who is jealous of Naruto's unique ability to control snow. This shinobi might secretly work against Naruto, trying to undermine his progress and steal the power for himself.

It could be an ancient evil that has been lurking in the shadows for ages. Maybe a dark spirit that was sealed away long ago and is now breaking free, and Naruto has to control the darkness within himself to fight it.

Perhaps a long - lost relative of the Potter family who feels they were unjustly excluded from inheriting the manor. This relative could be jealous of Harry's status and the wealth associated with the manor. They might use dark magic to try and claim what they think is rightfully theirs, leading to a battle of magic and loyalty within the Potter family and among Harry's friends.

Maybe there could be a new antagonist, a dark shapeshifter who is jealous of Harry's power. This antagonist could be an old wizard who has been in hiding for centuries, waiting for the right time to emerge and take over the wizarding world. He sees Harry as a threat to his plans and tries to eliminate him.