Gwen could be a great addition. She could be the voice of reason when Ben and Vilgax are at odds or she could have her own powers play a role in the story. Grandpa Max is also a good choice. His wisdom and experience could add depth to the fanfiction, especially when dealing with Vilgax. Another character could be Kevin. His ability to absorb energy could create some interesting interactions with Vilgax and also provide a different kind of friendship or rivalry dynamic with Ben.
Well, a plot could be that Vilgax gets amnesia and Ben has to decide whether to take advantage of this or help him. This could lead to a whole new dynamic between them as Ben tries to figure out what to do. Also, a fanfiction could explore what would happen if Vilgax became a mentor to Ben in a strange, alternate universe. They could train together and Vilgax could pass on some of his knowledge, but also try to manipulate Ben for his own ends. Or, perhaps a story where Vilgax and Ben are both stranded on a strange planet and have to work together to survive, all while dealing with their mutual distrust.
Power struggle is a common theme. Vilgax is always after more power and often clashes with Ben or other powerful beings in the fanfics. Another theme is revenge. Since Vilgax has been defeated by Ben many times, he often seeks revenge in these stories.
One popular 'Ben 10 Vilgax fanfic' could be 'Vilgax's Redemption'. It shows a different side of Vilgax where he tries to change his ways. Another one might be 'Vilgax vs. the New Aliens' which has some great action scenes with Vilgax facing off against newly introduced aliens in the Ben 10 universe.
One great 'Ben 10 Ben x Gwen Fanfiction' is 'Parallel Bonds'. It explores their relationship in an alternate universe where they have to work together against a new kind of enemy. The story is full of action and also delves into their emotional connection.
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 common theme is growth. Both Ben and Gwen grow as individuals and in their relationship. Another theme is friendship, as their bond is often a central part of the stories. Adventure is also a big theme, since they are from the Ben 10 universe and usually go on exciting adventures together.
Well, a klaus x ben fanfiction could explore their unique relationship. It might delve into their shared experiences in the context of their story world. For example, how Klaus's power of seeing the dead and Ben's situation as a ghost interact in the fan - created scenarios. It could also show their emotional bond, perhaps with Klaus relying on Ben in ways others don't understand, and Ben being protective of Klaus.
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.
A great fanfiction idea could be a story set in the future. Ben and Kevin are older and have trained new heroes. However, an old enemy resurfaces, but this time with a much more devious plan. The story could explore how their experiences over the years have changed them and how they use their wisdom and skills, along with their still - strong bond, to defeat the foe.