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.
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.
A possible plot could be that female Android 17 is captured by Orochimaru. Orochimaru wants to study her technology to enhance his own powers. Naruto, upon hearing this, decides to rescue her. Along the way, he has to face Orochimaru's minions and various traps. When he finally reaches Android 17, she is initially distrustful but Naruto convinces her that they need to work together to escape. They then form an unlikely alliance and fight their way out of Orochimaru's lair.
Naruto would probably be very curious about the female android servant. He might ask her a lot of questions about how she works and what she can do. He would also likely try to make her feel welcome, as he is a friendly person. For example, he might share his ramen with her, not really understanding that she doesn't need to eat.
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.
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.