Their relationship could develop in a very unique way. Imagine they land in a time where there is great danger. Kid Goku would jump right into action, and Android 18, seeing his courage, would join him. As they fight side by side, they would learn about each other's abilities and personalities. Android 18 could learn about Goku's love for his friends and family, and Goku could see that Android 18 has more to her than just being a powerful android. This could lead to a deep friendship or even something more in the long run.
At first, they might be at odds. Kid Goku is used to his own world and Android 18 is a product of a much different time. But as they face challenges together during their time travels, they could start to respect each other. For instance, Kid Goku might admire Android 18's strength and Android 18 could be intrigued by Goku's simple - minded yet brave nature.
Their relationship could develop into a deep friendship. Goku, being the kind - hearted fighter he is, would likely accept Android 18 for who she is. And Android 18, seeing Goku's strength and good nature, would start to respect him more and more.
Their relationship could become more of a teacher - student dynamic. Goku could teach Android 18 about the ways of the Saiyans and their fighting techniques from different eras during the time travel. Android 18, in turn, could show Goku some of her android - specific skills and how to use them more effectively. This exchange of knowledge could bring them closer and make them a more formidable team.
Their relationship could start off as a mutual respect for each other's power. Gohan would be in awe of 18's android abilities, and 18 would recognize Gohan's potential as a Saiyan. As they spend more time together, they might start to become friends, sharing their thoughts and experiences.
At first, they might still be competitive. But as they face the challenges of the different time periods together, they could start to respect each other more deeply. For example, if they are in a time when they are much weaker, they would have to rely on each other's skills more.
Well, they could end up in different historical events. Maybe they land during the Saiyan - Tuffle war. Kid Goku might be confused but Android 18 could use her knowledge of history (if she has any in this fanfic) to guide them. They could also meet different versions of characters, like a younger Vegeta or Gohan.
Well, at first they might be a bit wary of each other. But as time passed, they'd discover their common interests like the pursuit of strength. Goku's positive attitude would influence Android 18, and she would in turn help Goku with things like problem - solving from her android - smart perspective. As they grew older in the fanfiction, this relationship could become a very deep and important one, with them having each other's backs no matter what.
It could start as a mutual respect for each other's power. Goku would admire Android 21's combat abilities, and Android 21 would be intrigued by Goku's Saiyan strength.
One possible scenario in this fanfiction could be that Android 18 and Goku are forced to time travel due to a new threat that endangers the entire universe. They might travel to a time when the Saiyans first arrived on Earth. Goku, with his knowledge of the future, could try to change some events to prevent future disasters. Android 18, with her strength and unique abilities, would be a great ally in this adventure. They might face challenges like dealing with the primitive technology of that time and also having to hide their true identities to avoid disrupting the timeline too much.
If they travel to a time where they are younger versions of themselves, they could have a chance to start their relationship from a different perspective. They could become friends in a more natural way without all the baggage from their original timeline. As they grow up again in this new time, their relationship would be based on a deeper understanding and shared experiences, which would make it a more healthy and loving relationship compared to what they had originally.
Their relationship could develop in a very interesting way. Given Naruto's background of being an outcast in his village at first, he might be a bit hesitant to fully embrace Goku as a brother. But Goku's open - heartedness would gradually break down those barriers. Goku would introduce Naruto to his friends in the Dragon Ball world, and Naruto would do the same in the ninja world. They would start to share their stories, like Naruto's fight against Pain and Goku's battles against Frieza. Through these shared experiences, they would grow closer and closer, until they are inseparable brothers who are ready to take on any threat to their combined worlds.