There could be a lot of cultural clashes. The characters from Attack on Titan are used to a more medieval - like world with a focus on survival against Titans. The Lunar Chronicles characters come from a world with different social hierarchies and technological advancements. For example, Cinder from Lunar Chronicles might find the Survey Corps' way of life very primitive at first. But as they interact more, they start to understand and respect each other. They might even develop friendships that cross the boundaries of their two very different worlds.
The characters could start off as strangers and then gradually form alliances. For instance, Mikasa from Attack on Titan might be initially suspicious of the characters from Lunar Chronicles, but as they face a common threat, like a group of Titans or a powerful enemy from Lunar Chronicles' world, they start to work together. They could learn from each other's skills. Mikasa could show them her amazing combat skills with the blades, and the Lunar Chronicles characters could introduce her to their unique forms of technology or magic.
Well, it could be really interesting. The post - apocalyptic world of Attack on Titan with its giant Titans and the complex political and survival aspects could blend with the sci - fi and fairytale elements of Lunar Chronicles. Maybe the characters from Attack on Titan would find themselves in the high - tech yet also fairy - tale - like settings of Lunar Chronicles. They'd have to deal with the new technology and the different social structures there. And vice versa, the characters from Lunar Chronicles might be shocked by the Titans in the Attack on Titan world.
The characters from Pokemon, like Ash, would be very curious about the Titans. He might try to understand them first instead of immediately attacking. Meanwhile, the characters from Attack on Titan, such as Mikasa, would be initially cautious of the Pokemon. But as they see the Pokemon's powers, they would start to trust and work with them.
Luffy would probably be really excited to meet the Survey Corps. He'd see them as cool warriors and want to team up right away. He might even try to convince them to join his crew. Eren, on the other hand, would be a bit more suspicious. He's used to a world full of danger and betrayal, so he might not trust the Straw Hat crew immediately. But as he sees their loyalty to each other, he could start to warm up to them.
Well, Naruto is a very empathetic character. So when he meets Annie, he would probably try to understand her motives for her actions in Attack on Titan. He might think that there is some good in her, even though she has done bad things. And when it comes to the interaction between Naruto's friends and the Attack on Titan characters, there could be a lot of cultural shock. The ninja way in Naruto's world is very different from the survival - based mindset in Attack on Titan. But they could also learn from each other. For example, the Attack on Titan characters could learn about teamwork from Naruto and his friends, while Naruto's group could learn about the importance of adaptability from the people in the Attack on Titan world.
The 'Attack on Titan' characters would be quite shocked by the technology and the general chaos in the 'Gintama' world. Characters like Armin would be very interested in all the strange inventions and the way society functions in 'Gintama'. He might try to understand the economic and political systems there. And the 'Gintama' characters would be in awe of the 'Attack on Titan' characters' ability to fight Titans. They could team up to face common enemies or just have a series of comical misunderstandings that lead to all sorts of adventures.
The characters could interact through a shared goal. For example, if there's a new type of Titan threat that neither the 'Attack on Titan' characters nor Mel can handle alone, they have to work together. Eren might initially be distrustful of Mel, but as they face challenges together, they start to trust each other. Mikasa could be protective of Mel at first, seeing her as a vulnerable outsider in their dangerous world.
With Mikasa, she could become like a sister figure. Given Mikasa's protective nature, the reborn girl could be someone Mikasa feels the need to look out for. And they could share their experiences and thoughts, and together they might come up with new strategies for survival. As for Armin, she could engage in deep conversations with him about the mysteries of the Titans and the world outside the walls. She might have ideas that complement his intelligence and curiosity, and they could work together to explore new areas of knowledge related to the Titans.
Well, in this crossover, the Survey Corps members like Armin would be fascinated by the intelligence of some ghouls. They might try to communicate with them to gain knowledge about their powers. Ghouls like Touka would be in a difficult situation. She would be in a world full of titans, which are much larger and more difficult to deal with than the CCG in her own world. She might have to learn new fighting techniques from the Survey Corps. And characters like Erwin would see the ghouls as a valuable asset, trying to recruit them to fight the titans.
Eren could be really inquisitive about the Transformers' powers. He might try to learn from them how to better use his Titan - shifting abilities. The Autobots, like Bumblebee, would be friendly and try to communicate with the humans in their own way, which could be a bit difficult at first but they would manage.
Armin could be another good character for this. He's intelligent and good at strategizing. In a 'Attack on Titan meets FNAF' fanfiction, he could use his wits to try and understand the nature of the FNAF elements and come up with plans to either avoid or combat the threats that come from the combination of the two universes.