Dumbledore could be another character. He is extremely powerful and wise. He might have some prior knowledge or intuition about Alduin's existence. He could interact with Alduin in a more diplomatic way, trying to understand Alduin's motives and perhaps find a way to co - exist peacefully if possible. Or, if Alduin proves to be a threat, Dumbledore would be one of the few who could stand up to him.
Naruto would likely approach the female Alduin with his usual friendly and open - minded attitude. He would be curious about her and try to start a conversation. Alduin, depending on her personality in the fanfiction, might be aloof at first but Naruto's charm could break through her barriers.
Obviously, Naruto and Alduin would be the main characters. Naruto is the one being raised, so his growth and development under Alduin's influence would be central. Alduin, on the other hand, is the one doing the raising. His motives, his power, and his relationship with Naruto would be key aspects of the story.
I think Ron Weasley would be one of the characters likely to interact. He's always up for an adventure, and the wildness of Neverland would appeal to him. Ginny Weasley could also be involved. She's brave and strong - willed. From Peter Pan's side, Tinker Bell might interact with the Hogwarts students. She's feisty and would be curious about these new arrivals with different kinds of magic. And of course, the Lost Boys would be eager to meet the wizards and witches from Hogwarts.
Harry Potter himself could interact with Sophie from Huntik. Harry is used to facing great challenges and having a strong sense of justice. Sophie, with her connection to the Titans, could find common ground with Harry in their fight against evil. They could learn from each other's worlds and work together to overcome a powerful dark force that threatens both universes.
Definitely Harry Potter and Optimus Prime. Harry is the hero in the wizarding world, and Optimus is the leader of the Autobots. They both have a strong sense of justice and would likely team up to face big threats. Another pair could be Hermione and Bumblebee. Hermione's intelligence could be used to understand the Transformers' technology, and Bumblebee's friendly nature would make them get along well.
Hermione Granger and Albedo could also be characters that interact. Hermione is known for her intelligence and thirst for knowledge. Albedo is extremely intelligent as well in matters of strategy and magic in the Overlord world. They could exchange knowledge about their respective magic systems, like Hermione explaining the theory behind Transfiguration to Albedo.
One possible plot could be that Alduin somehow enters the Harry Potter universe. Maybe he is summoned by a dark wizard who wants to use his power to take over Hogwarts. Harry and his friends then have to figure out how to send Alduin back to his own realm while also dealing with the chaos the dragon has brought to the school.
Rebekah Mikaelson and Hermione would be likely to interact. Hermione is curious and intelligent, and she would be intrigued by Rebekah's different kind of magic. She would probably ask Rebekah a million questions about her vampire nature and the magic in her world. Rebekah, on the other hand, might be a bit annoyed at first but would come to respect Hermione's thirst for knowledge.
Obviously, Harry Potter and Riddick would interact. Harry, being the main hero in his world, would be curious about Riddick's strange abilities and his rough - and - tumble way of life. Riddick, on the other hand, would likely be suspicious of Harry at first but then come to respect his magical powers.
Definitely Harry Potter and Finn Hudson. Harry is the hero in the wizarding world, and Finn is a key figure in the Glee club. They could bond over their leadership roles. Harry could teach Finn some magic tricks, and Finn could show Harry how to be more confident while performing in front of a large audience.