For the characters of Frozen in the Fallout world, Elsa would have to learn to control her powers in a way that doesn't draw too much negative attention. She might start by using her powers secretly to help those in need. Anna would be quick to pick up on the survival skills of the Fallout characters. She would learn how to scavenge and barter. The Fallout characters would be amazed by Elsa's ice powers, but also cautious. They might try to find ways to incorporate her powers into their own survival strategies. In reverse, if Fallout characters entered Arendelle, they would be shocked by the beauty and peace. They would have to learn to communicate in a more formal and polite way, and respect the monarchy. The Frozen characters would be curious about the technology the Fallout characters might carry, and there would be a process of mutual learning and adaptation.
Well, consider Elsa from Frozen. If she were in the Fallout world, her ice powers could be used to preserve food in the wasteland, which is a very practical adaptation. She would also need to adapt to the violence and danger, perhaps using her powers defensively more often. The people in the Fallout world would need to adapt to her presence. Some might see her as a savior, while others might be afraid. Now, if a Fallout character like the Courier was in Arendelle, they would need to adapt to a more structured society. They would have to learn the rules and customs, and also deal with the magic which is completely foreign to them. Anna would likely be the one to help the Courier adjust, as she is very friendly and open - minded.
The Terrans from Starcraft would find the Pandora planet in Avatar very challenging. Their reliance on technology might not work as well in the lush and often unpredictable environment. They would have to learn to adapt to the natural cycles and the power of Eywa. The Na'vi, on the other hand, would be shocked by the mechanical and technological warfare of the Terrans. They might initially resist but could eventually learn to use some of the less harmful tech for their own benefit. For the Protoss, they would be intrigued by the spiritual connection in Avatar. They might try to find parallels in their own beliefs and use their psychic abilities to communicate with the natural forces on Pandora.
Well, Nick Wilde from Zootopia is a sly character. He might be able to adapt to the GTA 4 world more easily than some of the others. He could use his wits to blend in with the criminal underworld, perhaps even using their own tricks against them. In Zootopia, GTA 4 characters would have to adapt to a world where physical strength isn't always the most important factor. They might be surprised at how the Zootopia animals use their intelligence and unique abilities to solve problems and get by in their society.
The characters from Skyrim, like the Nords, are used to a cold and harsh environment. In the world of Game of Thrones, they might find the politics of Westeros very complex. However, their combat skills would be useful. For example, a Nord warrior could easily adapt to being a sellsword in Westeros. The characters in Game of Thrones, on the other hand, would be amazed by the magic in Skyrim. A character like Tyrion Lannister might be very interested in the Dwemer technology and magic.
The characters from Dark Souls are used to a world full of danger and death around every corner. In Game of Thrones, they would likely find the political intrigue and backstabbing to be just as dangerous as any monster. For example, a Dark Souls knight might initially be confused by the complex web of alliances and betrayals in Westeros but would soon learn to navigate it with their combat - hardened instincts.
Percy would probably have a tough time at first in the Warhammer world. The chaos and the different races would be quite a shock. But his ability to adapt quickly, which he learned from his many quests in his own world, would help. He'd start using his powers in new ways, like using water to put out the fires of the Dwarven forges when they go out of control. Annabeth would be studying the architecture and the different battle strategies of the Warhammer races, and try to incorporate them into her own knowledge base.
The Naruto characters would be shocked by the brutality and hopelessness of the Walking Dead world. Naruto, with his positive attitude, might try to inspire the survivors to keep fighting. The Walking Dead characters, on the other hand, would be in awe of the Naruto characters' powers. Rick might see Naruto as a potential leader with his ability to bring people together. Daryl would probably be interested in learning how to use a weapon like a kunai or shuriken.
If Gohan were to visit the Hidden Leaf Village, she would be introduced to the ninja academy and the training methods there. She might offer some suggestions based on her own training as a Saiyan. Naruto, when visiting Gohan's world, could be introduced to Capsule Corp and see all the amazing inventions. He might also get to meet Goku and Vegeta, and learn from their fighting styles. Their interactions would bridge the gap between the two very different universes.
The FNAF characters, if they were to enter the My Hero Academia world, would be very out of place. However, the animatronics' durability could be seen as a form of 'quirk' in that world. The heroes would have to figure out how to contain or deal with them. And the My Hero Academia characters would have to adapt their fighting styles to deal with these strange new opponents. For instance, Midoriya might try to find a non - violent way to subdue the animatronics at first, but if that fails, he'd have to use his full power.
Ruby would probably be excited by the new and different kinds of challenges in the Fallout world. She'd quickly learn to use the weapons she finds there while still relying on her Crescent Rose. Weiss would have a harder time adapting to the dirt and grime, but her determination would make her find ways to use her magic in this new environment. Blake would likely be more at ease in the shadows of the ruined buildings, using her stealth to her advantage.
Batman would find the world of Death Note very disturbing. The concept of the Death Note and the power it holds over life and death is something that goes against his sense of justice. He would be on a mission to stop anyone from misusing it. On the other hand, Light from Death Note might see Batman as a threat to his grand plan. Batman's reputation for thwarting criminals would make Light view him as someone who could expose his secret and put an end to his 'new world' vision.