Well, it could lead to a lot of chaos. Maybe Nico's friends from his own universe would try to rescue him. The Avengers might think he's a threat at first, but then realize they've made a mistake. It could also result in some interesting power clashes as Nico has his own set of powers and abilities.
Nico could initially be shocked and scared. But as he regains his composure, he would likely start to analyze the situation. He might try to communicate with the Avengers, especially if he realizes they are not pure villains. He would use his wits to find a way out of the situation while also trying to understand their motives for kidnapping him.
Nico's powers could also bring a new element of mystery to the Avengers. His abilities are not like the typical superpowers the Avengers are used to. This could lead to new training regimens and strategies. The Avengers would need to figure out how to incorporate his powers into their existing battle plans. And Nico himself would have to learn how to work within the group's dynamics, which could be a bit of a struggle at first given the differences in their power sources and fighting styles.
In many fanfictions where Gil gets kidnapped, it could be for various reasons. Maybe it's by a rival group who wants to use him as a bargaining chip against his friends. For example, in some stories, Uma's crew might be targeted because they are seen as a threat in the Isle of the Lost. Gil, being a part of that crew, gets kidnapped. Writers often use this plot device to create drama and show the loyalty and courage of the other characters as they try to rescue him.
Well, Nico could bring his unique powers, like his ability to control the dead in some ways. Maybe he'd help the Avengers with battles against supernatural foes that they might not be able to handle on their own. He could also form interesting relationships with the existing members, perhaps a friendship with Doctor Strange who also has some knowledge of the mystic arts.
The theme of self - discovery is also prevalent. Nico might learn new things about herself when she's around the Avengers. Maybe she discovers new aspects of her powers or her personality. And for the Avengers, they might also have a new perspective on their own abilities and roles when they meet Nico. It's like a journey of growth for all the characters involved in these fanfictions.
Natsu was walking through the forest one day when suddenly a group of dark mages emerged from the shadows. They quickly overpowered him with some sort of magic -binding spell. They dragged him away to an old, creepy lair. His friends back at the guild soon realized he was missing and set out on a search mission. Happy flew around frantically looking for any sign of his friend. Lucy, Gray and Erza teamed up and followed some leads they found in the forest. They were determined to rescue Natsu no matter what it took.
Peter's kidnapping was a carefully planned event. The kidnappers had been observing him for weeks. One day, as he entered a park, they grabbed him. They blindfolded him and took him to a secluded location. Peter was scared but he didn't show it. He started to befriend one of the kidnappers, a young guy who seemed a bit hesitant about the whole thing. Peter told him stories about his life and gradually the kidnapper started to have second thoughts. Eventually, the kidnapper helped Peter escape by distracting the others.
Nico is a character with a lot of internal struggle. His personality would add an interesting layer to the Avengers in fanfiction. He could bond with characters like Black Widow, who also has a troubled past. His quiet determination would be an asset during tough battles. And his ability to keep his emotions in check, most of the time, would be useful in high - stress situations. He might also bring a bit of dark humor to the team, a coping mechanism from his own difficult experiences.
It could be a new character created specifically for the fanfiction. Maybe a young scientist who is working on a project related to the super - soldier serum. Since Bucky has a history with the serum, this would create an interesting dynamic.