Well, let's consider Ben's alien form that can absorb energy. When combined with Hulk's raw power, they could create a situation where the alien absorbs Hulk's excess energy during his rage - filled moments. This would not only prevent the Hulk from causing too much destruction but also use that absorbed energy to power up the alien form for a more powerful attack. And in the case of Black Widow, Ben could transform into an alien with enhanced agility and stealth, and together with her combat skills, they could infiltrate enemy bases more effectively.
In this fanfic, perhaps the Avengers initially don't trust Ben because he's an unknown with such powerful and strange abilities. But then, when a common enemy attacks, like an alien race that wants to conquer Earth, Ben proves himself. He uses his different alien forms to complement the Avengers' skills. For example, using XLR8's speed to assist Quicksilver in a rescue mission. And throughout the story, they learn to work together and form a strong alliance.
One great idea could be Ben using his Omnitrix to transform into an alien that has a power similar to one of the Avengers. For example, turning into an alien with super strength like the Hulk and having a friendly competition with him. Another idea is that the Avengers could mistake Ben for a threat at first because of his alien forms and then they realize he's actually on their side. They could then team up to fight a common enemy, like a powerful villain from the Ben 10 universe that has somehow made its way into the Avengers' world.
Ben would probably be in awe of the Avengers at first. He might try to show off his alien forms to impress them. The Avengers, on the other hand, would be cautious. Tony Stark might want to study Ben's Omnitrix. Thor could be interested in the power of Ben's alien forms that are related to strength and lightning.
I really like the fanfiction titled 'Loki's Role in Avengers Assemble'. In this story, Loki is forced to work with the Avengers against a greater threat. It's full of action and interesting character dynamics. There's also 'Loki's Secret Mission with the Avengers' where Loki has a secret mission that only he can do, but he has to cooperate with the Avengers. And 'The Avenger - Loki' which gives Loki a more heroic role within the Avengers Assemble universe.
One great 'Marvel Avengers Assemble' fanfiction is 'The New Recruit'. It focuses on a new character joining the Avengers and how they adapt to the team's dynamics. It has really interesting character interactions and some cool action scenes.
One idea could be that Naruto is somehow transported to the Marvel universe where the Avengers are. He could use his ninja skills, like his shadow clone jutsu, to confuse the villains that the Avengers are facing. Maybe he teams up with Iron Man and they combine their tech and ninjutsu to create some really cool weapons or defenses.
First, you need to decide on the main plot. For example, a new threat emerges and the Avengers must reunite. Then, choose your favorite Avengers characters to include. You can start with the classic ones like Iron Man, Captain America and Thor. Next, create interesting dialogues for them. It's important to keep their personalities true to the original. For instance, Iron Man's witty remarks and Captain America's moral leadership. Finally, describe the action scenes vividly to make the fanfic exciting.
One great 'Avengers Assemble Tony Stark Fanfiction' is 'Stark's Redemption'. In it, Tony faces the consequences of his past actions in a very personal way. It delves deep into his character, showing his growth and how he interacts with the other Avengers. Another interesting one is 'Tony Stark: The Unseen Hero'. This fanfic focuses on Tony's behind - the - scenes contributions that often go unnoticed. He uses his intelligence and resources to solve problems that the Avengers might not even be aware of.
One great Steve Tony Avengers Assemble fanfiction is 'The Road to Redemption'. It focuses on Steve and Tony's complex relationship as they lead the Avengers. The story has amazing character development and some really exciting action scenes.