Well, in the 'naruto lifts thor's hammer fanfic', apart from Thor, other Asgardians like Heimdall could interact with Naruto. Heimdall, with his all - seeing ability, might have seen Naruto's worthiness from afar. The Hulk could also be involved. Imagine the chaos if the Hulk got jealous of Naruto having the hammer. And from Naruto's side, Kakashi could be there to guide Naruto on how to handle this new power that comes from a different world.
The main characters would be Percy and Thor for sure. Percy is the central figure in this scenario as he does the extraordinary act of lifting the hammer. Thor is important because it's his hammer. Additionally, Odin could be a character. As the All - Father in Norse mythology, he would have a great interest in Percy being able to lift the hammer. And from Percy's side, Grover could be there. He might be the one to provide some comical relief during the intense situations that arise from Percy having the hammer.
In this fanfic, Naruto might gain new powers or a special status. Since Thor's hammer can only be lifted by those worthy, Naruto lifting it could signify his great character. He could use the power of the hammer in battles against powerful foes in the Naruto universe, like Madara or Kaguya.
He could use the hammer as a tool in combat. Against his powerful foes in the Naruto universe, the hammer's unique abilities could give him an edge. For instance, he could use it to break through strong defenses that his normal jutsu couldn't penetrate. He might also use it symbolically, to inspire his friends and allies, just as Thor uses it in his own stories.
Sasuke would be a likely character to interact. Given their complex relationship throughout the Naruto series, Sasuke might be suspicious or intrigued by Naruto's control over Zetsu. Their interactions could range from confrontations to reluctant teamwork.
Obviously, Koyuki herself would be a main character to interact with Naruto. She might show him around her place, introduce him to her people. Also, any of her loyal guards or advisors could interact with Naruto. They could be initially suspicious of him but then grow to trust him as they see his good intentions.
He might be initially confused about how to use it. But once he figures it out, he could start using it like he does his ninja tools, just with much more power. He'd probably hold it in one hand and still be able to do his hand - signs for ninjutsu with the other.
Sasuke would likely be one of the main characters to interact with Naruto. Given their complex relationship, Sasuke might be either supportive or skeptical of Naruto's newfound power. Sakura could also be involved, perhaps trying to heal Naruto if the dark power has negative effects on him. Kakashi would surely step in as well, using his wisdom to guide Naruto and make sure he doesn't lose himself in the darkness.
Obviously, Sasuke would still be a major character she interacts with. Their relationship could be even more complex now that Naruto is a girl. Sakura might also have a different dynamic with Naruto. Instead of seeing her as a rival for Sasuke's attention, they could become closer friends and train together more often.
There could be many people who created such fanfiction. It might be an individual writer who is a big fan of both the Spider - Man and Thor characters and wanted to see what would happen if Peter could lift the hammer. It could also be part of a fanfiction community where different people contribute ideas and sometimes collaborate on stories.
Sasuke would be a likely character. Their rivalry could take on a new dimension as Naruto's super intelligence might make Sasuke more intrigued or even a bit jealous. They could have more complex conversations about strategy and the future of the ninja world.