Well, in a dbz justice league fanfiction, there could be a plot where the power levels of the Justice League members are measured using the scouters from DBZ. This could lead to some interesting reactions. Superman might have an off - the - charts power level that astonishes the Z - fighters. At the same time, the Justice League could learn some ki - based techniques from the DBZ characters. For instance, Aquaman could learn how to fly using ki, which would be a huge advantage for him in underwater and above - water battles.
A cool plot could be a race between The Flash and Gotenks. They both pride themselves on their speed, so it would be interesting to see how that pans out. Also, perhaps Vegeta could befriend Batman as they both have that brooding, serious personality. They could exchange combat and strategy tips. And what if the Dragon Radar was used by the Justice League to track down an energy source that was causing chaos in both universes?
In DBZ and Justice League fanfiction, a common concept is the idea of training together. For instance, the Saiyans could teach the Justice League members how to harness their ki. This could lead to new power - ups for the Justice League characters. Another aspect is the exploration of different moral codes. The Saiyans have a different view on combat and honor compared to the Justice League. Fanfiction can delve into how these two groups might influence each other's perspectives. There could also be a story where the villains from both universes team up, forcing the heroes from DBZ and the Justice League to combine their forces to stop them.
One idea could be a tournament where the Z - fighters from Dbz and the Justice League members compete. For example, Goku could be paired against Superman in a friendly yet intense battle to see who is stronger in terms of physical strength and combat skills. Another plot could involve a common enemy that forces the two groups to team up. Maybe Darkseid and Frieza form an alliance and the combined forces of the Dbz characters and the Justice League have to stop them.
One idea could be a crossover where the Young Justice team has to team up with the Justice League to face an interdimensional threat. Maybe a powerful villain from another dimension is trying to invade Earth and the combined skills and powers of both groups are needed to stop it.
Maybe a story where some of the younger members of the Young Justice team are frustrated with the Justice League's methods and decide to take on a mission on their own, but end up getting in over their heads and have to call in the League for help. This could lead to a lot of character development and some interesting dynamics between the two groups.
One idea could be Izuku getting accidentally transported to the Justice League's universe. He could then use his unique Quirk to help the Justice League in a battle against a powerful new villain that they're having trouble with. For example, his One For All power could give him the strength to hold back a giant monster while the League figures out a more permanent solution.
Another interesting plot could be that a powerful villain creates a device that can steal powers. He targets both Ben's aliens and the Justice League members. Ben and the League have to find a way to stop the villain before they lose all their powers. They go on a wild adventure across different dimensions to find the parts needed to destroy the power - stealing device.
A cool concept could be a 'Batman Justice League fanfiction' set in an alternate universe where the League is formed much earlier in history. Batman has to adapt to working with heroes from different time periods and cultures, and they all have to figure out how to use their powers in a world that's not as technologically advanced as their own.
One idea could be exploring the backstories of the lesser - known members in more depth. For example, you could focus on a character like Blue Beetle and his struggle to control the Scarab while also fitting into the team. Another idea is to create an alternate universe where the Justice League is evil and the Young Justice League has to oppose them. This would lead to some really intense battles and moral dilemmas for the young heroes.
One idea could be that the Young Justice team gets accidentally transported to an alternate dimension where the Justice League has turned evil. The Young Justice members then have to figure out how to reverse the situation while also evading capture from their once - heroes. Another could be a time - travel plot where the Young Justice team travels back in time and teams up with the early days of the Justice League to stop a threat that was thought to be long gone but has resurfaced in their own time. A third idea is that a powerful new villain emerges who can only be defeated by a combined effort of the Young Justice and Justice League, but first they have to overcome their differences in fighting styles and leadership.