Ben is an obvious choice as he is the main character. His different alien forms offer a lot of possibilities for storylines. Gwen is also great as she has her own powers and a complex relationship with Ben. And of course, Kevin, with his unique abilities and his friendship - turned - rivalry - turned - friendship again with Ben.
Definitely Ben, since he is at the center of the whole Omniverse concept. His character growth throughout the series gives a lot to work with. However, don't overlook characters like Rook. He has an interesting backstory and his loyalty to Ben can be explored in fanfiction. Also, Vilgax is a classic villain that can add a lot of drama and action to a story.
In 'ben 10 omniverse fanfiction', Ben is a must - focus character, but other characters like Azmuth can be really interesting. He is the creator of the Omnitrix and his knowledge and motives can be delved into. Then there's Eon, a powerful and mysterious character. A fanfiction exploring his origin and his connection to Ben could be really engaging. Also, characters like the Plumbers can be used to create a more complex world - building in the fanfiction.
The main characters are obviously Ben and Kai. Ben is the wielder of the Omnitrix, which gives him the power to transform into various alien forms. Kai is a strong - willed and adventurous character who often gets involved in Ben's escapades.
One possible fanfiction could be about Ben and Kai going on a new adventure in the Omniverse. Maybe they discover a new alien species that is causing chaos in a far - flung galaxy. Ben uses his Omnitrix to transform into different aliens to try and stop the threat, while Kai uses her martial arts skills to fight alongside him.
The main characters are Ben and Kai. Ben is a heroic figure with the Omnitrix, which is a device full of alien DNA that he can use to transform. He is brave and always ready to protect the Omniverse. Kai, on the other hand, is a feisty and determined character. She brings her own charm and abilities to the story. In a 'Ben 10 Omniverse Ben x Kai' fanfic, these two are the focus. Their different personalities clash and complement each other as they navigate the dangerous and exciting world of the Omniverse together.
There's also a chance that it could be a former enemy of Ben who has a grudge. They might want to get revenge on Ben by kidnapping him and putting him in a difficult situation. It could also be a mad scientist who wants to study Ben's alien forms and the Omnitrix, so they kidnap him to do all sorts of experiments on him.
Well, in a fanfiction, they could be on a mission to save a planet that is on the verge of destruction. Ben uses his alien powers to hold off the immediate threats, like asteroids or attacking creatures, while Kai tries to find the root cause of the planet's problems, which could be some sort of evil technology or a corrupt leader.
One great Ben x Kevin fanfiction could be about their adventures in a parallel dimension. In this story, they might face new aliens and challenges that test their friendship even more. Maybe they find a powerful alien artifact that only works when they combine their unique abilities, leading to a deeper understanding of each other.
One popular character could be Gwen from the Ben 10 series, especially when she is incorporated into Omniverse fanfiction. She has her own set of powers and a strong personality. In fanfiction, she can be a great support or even a rival to the female Ben.
Kevin Levin can be a really cool addition. His ability to absorb materials and transform into different forms makes for some exciting action scenes. Also, his complex backstory can create interesting storylines when combined with the reader's character, like if the reader helps him come to terms with his past or something similar.
Definitely Ben Tennyson himself. He's the main character and the one with the Omnitrix. His different alien forms like Heatblast, Four Arms, and XLR8 can add a lot of action and variety to the story.
Ben and Kai are likely candidates. Ben is the hero with the Omnitrix, and Kai is his adventurous and tough - minded friend. Their dynamic of going through dangerous situations together could easily lead to a romantic relationship.