Friendship is a common theme. It could show how their friendship develops over different adventures in the Ben 10 universe.
Another theme could be mutual respect. As two characters from different backgrounds, they learn to respect each other's cultures and ways of doing things in many 'ben x rook fanfic'. It can be a really interesting exploration of their relationship dynamics.
There could also be a theme of self - discovery. As they interact, both rook and ben might discover new aspects of themselves. For example, rook might learn more about his own courage through his association with ben, and ben might understand the importance of loyalty better because of rook. This self - discovery can be a really interesting theme to explore in fanfic.
Another theme is adventure. Since they are from a universe full of strange planets and creatures, many fanfics take them on exciting adventures across the galaxy. They might be searching for a powerful artifact or trying to stop an evil force from taking over the universe. It's all about the journey and the discovery along the way.
Friendship is a very common theme. Their bond as partners in protecting the universe is often explored in depth.
Another theme is growth. Both characters can grow and learn from each other. Ben might learn more about Rook's culture and values, and Rook can learn about Ben's more impulsive but brave nature. This mutual growth helps to strengthen their relationship in the fanfiction stories.
One common theme could be the exploration of their relationship in different scenarios. For example, in some fanfictions, they might be facing a dangerous situation together which brings them closer. Another theme could be the development of their feelings over time, from just being comrades to something more romantic.
By having them face a common enemy. When they fight side by side against a powerful foe, they can learn to trust each other more and understand each other's fighting styles better.
One possible plot could be that Rook and Ben go on an adventure to a new planet in the Ben 10 Omniverse. They encounter a strange alien species that has a unique power. Ben tries to use his Omnitrix to transform into an appropriate alien to deal with the situation, but there are some glitches. Rook, with his Plumber skills, helps Ben figure out what's wrong and together they overcome the challenges and make new friends among the aliens.
One possible 'ben x rook lemon fanfic' could be about their adventures together in a post - apocalyptic world where they have to rely on each other. Their relationship deepens as they face challenges, and the lemon aspect could be a passionate moment they share during a quiet interlude in their journey.
Perhaps a fanfic where Ben and Rook accidentally swap abilities. Ben has to deal with Rook's weaponry and combat skills, while Rook tries to control the Omnitrix. It would be full of comical moments as they struggle to adapt, but also a chance for them to learn more about each other's strengths and weaknesses.
In these fanfics, the theme of teamwork is everywhere. Ben and Rook are a team, and exploring how they work together, divide tasks, and combine their skills is a big draw. For example, Ben's brute force with his alien powers and Rook's strategic thinking. Additionally, the theme of facing fears comes up a lot. Both characters have their own fears, and seeing them overcome those in the fanfictions is quite appealing. And of course, the theme of exploring new planets and civilizations, which is a natural extension of Ben's alien - transforming abilities and their intergalactic adventures.