Family dynamics is another. As brothers, their relationship can be complex. Some fanfics show loyalty between them, while others highlight jealousy or rivalry. For example, a fanfic might explore how Frieza's jealousy of Cooler's strength affects their relationship.
The allure lies in the fact that we can see these two powerful villains in new situations. In fanfiction, they might interact with characters from other universes, which is really cool. It expands the Dragon Ball Z universe in ways the original didn't.
Power is a common theme. Since both Frieza and Cooler are powerful characters, many fan fictions explore how they gain more power, or how they compare their power levels. Another theme is family. Their relationship as brothers often plays a big part, like in stories about their rivalry or their attempts to cooperate. Redemption can also be a theme, especially for Cooler in some fictions where he tries to make up for his past actions.
Fanfiction also allows for different endings to their stories. Instead of their fates in the original series, they could be redeemed in some fanfictions. Picture Frieza actually learning to care about others and using his power for good. It's a different take on their characters that fanfiction can offer.
Another good one is 'Frieza and Cooler: Allies in a New World'. This fanfic imagines a scenario where they have to team up against a greater threat than they've ever faced before. It's full of action and shows how their powers combine in different ways.
One popular 'Frieza and Cooler' fan fiction is 'The Brothers' Rivalry Extended'. It delves deeper into their relationship, showing how their competitiveness affects their actions within the Frieza Force. Another is 'Cooler's Redemption', where Cooler tries to atone for his past misdeeds and Frieza has to deal with this new side of his brother. There's also 'Frieza and Cooler: A New Alliance' which imagines them teaming up against a common, powerful enemy that threatens their rule in the universe.
A plotline could start with Frieza hearing about Broly's power and being jealous. He then devises a plan to ambush Broly. But Broly, being extremely perceptive in his own way, senses Frieza's approach and is ready for the fight. As the fight progresses, Frieza realizes that Broly is much stronger than he expected and has to use all his dirty tricks to try and win. Or perhaps the plotline could involve Broly being captured by Frieza's forces, and then Broly breaks free and goes on a rampage against Frieza and his minions.
One of the main themes is the clash of generations. Goten represents the new generation of Saiyans while Frieza is from an older, more menacing era. This creates an interesting dynamic. Survival is also often a theme, as Goten has to fight to survive against Frieza's brutal attacks. Additionally, the theme of justice can be seen, where Goten is fighting for what he believes is right against Frieza's tyranny.
A possible fanfiction could focus on a group of Saiyans who are trapped in a dimension where they can only watch the Goku vs Frieza fight on repeat. They start to notice small details in the fight that they hadn't before, like the exact moment Goku's power level spikes or how Frieza is trying to adapt his strategy. This newfound knowledge could then be used by them in some way when they eventually break free from that dimension.
Trunks would also be interested. He has his own experiences with fighting powerful foes and would be eager to see how Goku, a great Saiyan warrior, fares against Frieza. Also, the younger Saiyans like Goten might be interested. They've heard stories about Frieza and would be excited to see their father or other Saiyan heroes in action against such a notorious villain.