Well, he might be really confused at first. Middle Earth has its own unique magic system and races. Harry, with his Hogwarts - trained magic, would have to adapt. He could probably make friends with some of the elves, like Legolas, as they both have a sense of honor and skill in archery. And his encounter with Gandalf would be really interesting, as they are both powerful wizards in their own ways.
The wizard Gandalf would be an obvious character for Harry to interact with. They are both wizards, though from different worlds. They could share their knowledge of magic, and Gandalf could guide Harry in the ways of Middle Earth while Harry could introduce some new magical concepts to Gandalf.
Harry's magic is more about instant spells using his wand. In Middle Earth, magic seems more subtle and connected to the land. But Harry's powerful offensive spells like the Stunning Spell could be quite effective. His ability to fly on a broomstick would be a unique advantage. However, the wizards in Middle Earth, like Saruman and Gandalf, seem to have a more profound understanding of the deeper magic of the world.
Well, perhaps Harry would be super confused at first. He'd find himself in a world full of different races like hobbits, elves, and dwarves. Maybe he'd use his magic to help in the fight against Sauron. He could teach the people of Middle - earth some new spells or ways of magic that they've never seen before.
One possible plot could be that Harry Potter somehow gets transported to Middle Earth. He might use his magic skills to help in the battles against the dark forces there. Maybe he forms an alliance with the Fellowship of the Ring and uses his knowledge of facing dark wizards like Voldemort to take on Sauron.
Well, in such a fanfiction, Harry Potter would have to adapt to Middle Earth's cultures. The elves might teach him their refined ways of magic. And he may use his broomstick in a very different landscape, perhaps flying over the Misty Mountains. His presence could also change the fate of Middle Earth as he has a strong sense of justice.
One possible plot could be that Naruto is mistaken for a powerful wizard when he arrives in Middle - earth. He then has to prove himself to the various races there. Along the way, he uses his rasengan to blast through orc hordes and his shadow clone jutsu to create distractions during battles. He also learns about the magic of Middle - earth and tries to combine it with his own ninja powers.
She could fit in as a powerful ally. Her skills in magic, like casting spells and using potions, would be valuable in Middle - earth. For instance, her ability to perform defensive spells could protect the inhabitants from various threats.
Well, he might bring his magic from the wizarding world to Middle - earth. Maybe he'd use spells to fight against the dark forces there like Sauron. He could also make friends with the hobbits, elves and dwarves, teaching them some new magic tricks.