Well, for Tony Stark, he might become a bit more laid - back around the Guardians. The Guardians' carefree attitude could rub off on him. He may start to make more jokes and not be as uptight about his technology and plans.
Peter Quill might become more responsible in the presence of the Avengers. He sees how they have a more organized approach to saving the world, and it makes him want to step up his game. He might start to think more about the long - term consequences of his actions instead of just living in the moment.
One exciting plot could be that the Guardians and the Avengers have to team up to stop a powerful cosmic villain who is collecting powerful artifacts from both Earth and other planets in the galaxy. The Guardians' knowledge of the galaxy and the Avengers' understanding of Earth could be combined to track down the villain.
One exciting plot twist could be that the Infinity Stones have a different origin in this fanfic. Maybe they were created by an ancient race that both the Avengers and Guardians have to discover together. This would force them to work closely and share their knowledge.
One idea could be that the Infinity Stones are scattered across different planets again. The Avengers and the Guardians have to team up to find them before a new villain does. Maybe Thanos has a long - lost relative who is out for revenge and wants to use the Stones' power for destruction.
I think the meeting between Thor and Groot would be fascinating. Thor, being an Asgardian god, and Groot, a sentient tree - like creature. Thor might be initially confused by Groot's limited vocabulary ('I am Groot'), but as he gets to know him, he would see Groot's strength and loyalty. Groot could also be intrigued by Thor's lightning powers. And their combined strength in a fight against a common enemy would be a sight to behold.
Definitely Thor and Star - Lord. Thor is this god - like being from Asgard, and Star - Lord is a half - human, half - alien space adventurer. Their personalities are quite different. Thor is more noble and straightforward, while Star - Lord is a bit of a scoundrel. But they both have a sense of humor and a love for adventure. They could have some great banter while fighting side by side.
Another theme is teamwork. When they cross over with teams like the X - Men, both groups have to learn to work together despite their differences in powers and ideologies. This often leads to some really cool battle strategies and character development.
When it comes to how the characters' personalities change in this crossover, it's quite complex. Marinette, as Ladybug, may start to show a more vulnerable side. The beauty and danger of the Swan Lake world make her realize that she can't always be in control. Chat Noir might become more solemn. The grandeur and the dark undertones of Swan Lake could make him more aware of the seriousness of their situation. And for other characters like Chloe, she could either be completely out of her depth and become more submissive or, in a twist, she could try to take on the role of a villain within the Swan Lake story, using her mean - girl tactics in a different, more magical context.
Castiel's stoic and somewhat naïve personality in Supernatural would contrast with the more worldly and sly characters in Good Omens. However, his loyalty and sense of duty could be something that the Good Omens characters would admire. And in return, the Good Omens crew could teach Castiel to loosen up a bit and not be so rigid in his thinking.
Belle is known for her love of books and her intellectual curiosity. In the crossover, she might be the one to study Elsa's powers from a scientific or historical perspective. The Beast, on the other hand, is gruff but kind - hearted. He might be a bit more cautious around Elsa's ice powers at first. Anna is impulsive and full of energy. She would likely be the one to drag Belle and the Beast into adventures. Elsa is more reserved and has a sense of self - isolation due to her fear of her powers, which is very different from Belle's outgoing nature when it comes to exploring the castle.
On the other hand, some of the more stoic Gundam pilots might be taken aback by the more flamboyant personalities in Infinite Stratos. However, over time, they could learn from each other. The Gundam pilots could pick up on the IS pilots' ability to be more flexible in combat due to their different mecha designs, while the IS pilots could learn about long - term strategic planning from the Gundam pilots.