There could be. Fanfiction is a vast world where all kinds of crossovers happen. Given the popularity of both Naruto and Android 21, it's not far - fetched that someone has written a story about them. However, finding it might take some time. You could start by looking on major fanfiction websites and using relevant search terms to see if such a work exists.
One idea could be that Android 21's unique powers attract the attention of Naruto. He might see her as a new kind of challenge. Maybe she has some sort of energy that is similar to chakra in a way. And Naruto tries to understand her and her powers, leading to an unexpected friendship.
In Naruto Android fanfiction, a common theme is adaptation. Naruto has to adapt to being an Android, whether it's learning how to use new Android - like abilities or fitting into an Android - dominated society. Another theme is friendship. Just like in the original Naruto story, he might form new friendships with other Androids or humans in this new fanfiction setting. And technology vs. nature could also be a theme, as Naruto's natural ninja powers contrast with the artificial nature of Android technology.
Naruto would probably be very curious about Android 21. He'd likely approach her with his usual friendly and open - minded attitude. Android 21 might be a bit reserved at first, but Naruto's enthusiasm could break the ice. They could start by just talking about their different abilities.
Naruto and Android 21 might interact in various ways. At first, Naruto would probably be very curious about Android 21. He's used to dealing with all kinds of strange things in his world, but Android 21 would be a whole new level. Android 21 could be interested in Naruto's physical abilities and chakra system. She might try to approach him in a friendly way to study him, but Naruto, being a ninja, would be cautious. Eventually, they could either become friends if Android 21 proves she has good intentions or remain enemies if she tries to harm Naruto or his friends.
Well, in the world of fanfiction, anything is possible. Naruto comes from the Naruto universe which has its own set of rules and relationships. Android 18 is from the Dragon Ball series and Bulma too. Combining these three characters in a romantic context is a very creative and out - of - the - box idea. It would require a lot of imagination to make it work. For example, you'd have to find a way to bridge the different power levels, cultures, and personalities. But in fanfiction, fans can break all the rules and create a unique and interesting story.
Naruto would probably be very curious about Android 21. He'd be asking her a lot of questions about where she came from and what her powers are. Android 21, on the other hand, might be initially confused by Naruto's overly friendly and energetic nature.
Another fanfiction concept could be that female Android 17 has been sent to the Naruto universe by some unknown force. Naruto, being the curious and friendly ninja he is, tries to befriend her. He shows her the ways of his village, and she in turn teaches him some of her combat techniques, leading to an interesting exchange of cultures.
One common theme is the clash of different power systems. Naruto has chakra - based powers, while Android 21 has her android - related abilities. Fanfictions often explore how these two different power systems interact.
One great 'Naruto Android Fanfiction' is 'The Android Ninja'. It has an interesting plot where an android with Naruto's memories is created. The story is full of action as the android battles against old enemies in new and exciting ways.