One common theme is redemption. Since Raditz is initially a villain in the Dragon Ball series, many fanfictions focus on how a female character can bring about his redemption. For example, through her kindness and understanding.
Another theme is the exploration of relationships. This could be romantic relationships between the female character and Raditz, or platonic ones where the female acts as a mentor or friend. In some fanfictions, the female helps Raditz adapt to Earth's culture, which is also a form of relationship building.
Power - up is also a theme. The female character might have some special ability or knowledge that helps Raditz become stronger. For instance, she could introduce him to new training methods or have some kind of magic that enhances his Saiyan powers.
Love against all odds is a theme that often appears. Given their different backgrounds, a relationship between Raditz and Chichi would face many challenges. But fanfiction writers might explore how their love can overcome things like differences in power levels, the disapproval of others (both Saiyans and humans), and the general chaos of the Dragon Ball world.
One common theme is rivalry turned friendship. Since they are both Saiyans, they start off with a sense of rivalry but then develop a deeper bond in many fanfics.
One possible theme could be power dynamics. Given the 'slave' aspect, there would likely be a significant exploration of how power is distributed between Chichi and Raditz. Another theme might be redemption. Raditz is often seen as a villain in the Dragon Ball series, and this relationship could potentially be a way for him to redeem himself through his interactions with Chichi.
If Raditz survived in fanfiction, he would likely have a complex relationship with Goku. He might start to see the value in Goku's way of life. Goku could try to reform him, and Raditz could slowly become a more positive force in the Dragon Ball Z universe.
Common themes in 'Dragon Ball Z Raditz x Bulma fanfic' often include the clash of their different worlds. Raditz comes from a warrior - based Saiyan culture, and Bulma from a more technologically advanced Earth culture. So there could be a theme of how they learn from each other. Also, themes of love against all odds can be present, as their relationship would be quite unorthodox in the context of the original Dragon Ball Z story.
It could lead to a completely different story arc. Raditz's change of heart might influence Goku and the others' relationships and battles.
One common theme is family dynamics. Since Trunks has a family connection with Bulma, and Raditz being an outsider, the fanfics might explore how Raditz fits into or affects that family unit. Another theme could be redemption. Raditz was initially a villain, so fanfics could show him redeeming himself in the eyes of Bulma and Trunks.
One popular female Raditz fanfiction is 'The Redemption of Raditz'. It focuses on a female character who befriends Raditz and tries to change his ways. Another one is 'Raditz's New Path' which explores Raditz's journey with the help of a female protagonist.
Family ties are a key element. Since they are brothers, fanfictions often explore their complex relationship, like how they deal with their Saiyan nature versus the influence of Earth. For example, in some, Goku tries to make Raditz understand the importance of protecting the planet.
Raditz could be redeemed by sacrificing himself for the greater good. For example, if there was a powerful enemy threatening the Earth and he steps in to take a fatal blow meant for someone else, like Gohan or Goku.