Who could be a good antagonist in 'naruto x female elf fanfiction'?

Perhaps a dark elf from the elf OC's world who has turned bad. This dark elf could be jealous of the elf OC's connection with Naruto and the Naruto world. So, he follows the elf OC to the Naruto world and tries to disrupt their friendship and cause chaos. He might have some dark magic that is a threat to both Naruto and his friends as well as the elf OC.

It could be an evil elf who has been exiled from their own elven community for practicing dark magic. This elf might see the Ninja world as a place to gain more power and cause chaos. They could target Naruto specifically because they sense his strong chakra and want to either steal it or use him as a tool for their evil plans.

It could be an evil ninja who wants to capture the female wolf for her unique powers. Maybe he plans to use her chakra to create a powerful weapon or perform a dark jutsu.

It could be a rogue ninja who wants to capture the female werewolf for her unique powers. He might see her as a tool to gain more power in the ninja world.

It could be a powerful dark wizard from the Enchantress' world who follows her to the Naruto universe. He wants to capture the Enchantress and use her powers for his evil plans, and also sees the chakra in Naruto's world as a new source of power to conquer. He could have dark magic that can nullify ninjutsu, creating a real challenge for Naruto and the Enchantress.

Perhaps a powerful demon that has a grudge against the power of Amaterasu. It targets Naruto because he is the one who seems to be getting closer to Amaterasu. The demon could be from an ancient time when Amaterasu was first used to seal it away, and now it's back to stop Naruto from fully understanding and using Amaterasu.

Kawaki could also be a potential antagonist. If he feels that Delta's connection with Naruto is a threat to his own place in Konoha or his relationship with Naruto, he might act against them. He has a complex past and his insecurities could drive him to oppose their alliance.

Mephisto could also be a great main antagonist. His ability to corrupt and manipulate could pose a real threat to Naruto. Mephisto might try to turn Naruto's friends against him or corrupt Naruto himself. Since Naruto values his comrades highly, this would be a difficult situation for him to deal with. And if Mephisto manages to get into Naruto's head, it could lead to some really intense and dark moments in the fanfiction.

It could be a rogue ninja from a long - forgotten clan. This ninja might see the growing relationship between Naruto and Sara as a threat to his own plans for power. He could try to disrupt their villages' alliance and target them specifically.

It could be another Predator. Maybe a rogue Predator that doesn't follow the code of its kind. This rogue Predator might see Naruto and his friends as a threat to its own plans in the Naruto world and tries to eliminate them. It could also use its advanced technology against them in cruel ways, making it a formidable antagonist.