A fanfic could focus on Noah's perspective of being Rex's friend. Maybe Noah starts to feel a bit overshadowed by Rex's powers and has to deal with his own insecurities while still supporting Rex in their adventures. For example, during a mission where Rex is getting all the glory, Noah could be the one who actually figures out the key to defeating the EVO, but no one notices at first.
In a more adventurous fanfic, Rex and Noah could accidentally be transported to a parallel dimension where the rules of the world are different. Here, Rex's powers don't work as expected and Noah has to use his tech - savvy skills to figure out how to get them back home. They could meet alternate versions of their friends and enemies along the way.
First, you need to understand the characters. Rex is brave and has his powers, while Noah is more of the brains and tech support. Start with a simple plot, like they discover a new EVO threat. Then, build the story around their interactions and how they use their respective skills to deal with the situation.
Another story could be set in a post - apocalyptic world where vampires have emerged as a result of some mutagenic event related to the nanites. Rex, being the only one with the ability to control his nanites, has to find a way to coexist with the vampires. He could encounter a vampire who was once a scientist and together they try to reverse the vampiric transformation in some people.
One idea could be a crossover where Generator Rex's nanites interact with the X - Men's mutant powers in unexpected ways. Maybe the nanites start to adapt and mimic some of the mutant abilities, causing chaos and confusion among both groups.
One idea could be that Naruto and Rex meet in a dimension where their worlds collide. Naruto's chakra powers and Rex's nanite abilities could create some really interesting battle scenes as they team up against a common enemy, like an evil organization that wants to control both their worlds.
One possible fanfiction could be about Rex's adventures in a new, uncharted area where he discovers a strange new type of E.V.O. He has to use his powers in creative ways to deal with it and learn more about this new threat or ally.
One idea could be a crossover with Ben 10. Rex's nanites and Ben's Omnitrix could lead to some interesting power clashes and team - ups. They could face a common enemy that requires both their unique abilities to defeat. For example, an alien - nanite hybrid villain.
Fanfiction about Rex and Six could also involve a mission where they are sent undercover. They have to pretend to be ordinary people in a community that is on the verge of being overrun by E.V.O.s. They need to figure out how to stop the E.V.O.s without blowing their cover, and in the process, they learn more about each other's personalities outside of the battlefield.
In a fanfiction crossover, they could end up in each other's universes by accident. Ben finds himself in a world full of EVOs and has to rely on Rex to get back home. Meanwhile, Rex is intrigued by the Omnitrix and tries to figure out how it works. They face many challenges together, like dealing with Rex's old enemies who see Ben as a new target.
Once upon a time, Generator Rex was exploring an old, abandoned facility. There, he encountered the Black Knight. The Black Knight was initially cautious of Rex. However, Rex was curious about the Black Knight's origin. As they interacted, Rex showed off his nanite - based abilities, like creating various weapons from his body. The Black Knight was impressed and decided to share some of her secrets with Rex. Together, they decided to face a new breed of EVOs that were causing chaos in the city.
Yes, there are quite a few. Some might focus on their adventures together in a post - apocalyptic world. For example, they could be on a mission to save their community from a new threat.