A fanfic about the backstory of one of the minor kaiju in Kaiju no 8 could be really interesting. Maybe it was once a normal creature that got mutated due to some scientific experiment gone wrong. You could explore its journey from a normal being to a kaiju and its feelings about it.
Another idea is a time - travel fanfic in Kaiju no 8. The characters go back in time to prevent the first kaiju appearance. They would have to deal with the challenges of changing the past without causing even more chaos.
One idea could be a fanfic where the main character has a unique power to communicate with the kaiju. This would add a new dimension to the story as they could try to negotiate with the kaiju instead of just fighting them.
Well, you could write a fanfic where a new type of kaiju is introduced into Kaiju Paradise. This kaiju has unique abilities that no one has seen before. The main character is a scientist or a researcher in the park who tries to study this new kaiju. Along the way, they face challenges from the park's management who don't want the public to know about this new discovery, and also from the kaiju itself which is very unpredictable.
One idea could be a kaiju fanfiction where the kaiju form an alliance with humans to fight against an even greater threat from outer space. It would be a unique twist on the usual kaiju - human conflict.
One interesting idea could be the RWBY characters having to team up in new ways to combat the kaiju. For example, Ruby's speed might be used to quickly dodge a kaiju's attacks and find its weak spots. Another idea is the fusion of Dust technology with kaiju - like elements. Maybe they create new weapons that can both harm the kaiju and also harness some of their power. Also, the idea of kaiju having Aura or semblances of their own could be really cool, changing the dynamics of how the RWBY characters interact with them.
One idea could be a human who gains kaiju - like powers through a scientific experiment gone wrong. They then have to deal with the consequences of their newfound strength and the fear of society. Another could be a world where humans and kaiju co - exist, and a human befriends a kaiju and they go on adventures together. A third idea is a group of humans who have to fight off an invasion of kaiju using their wits and some stolen kaiju technology.
One idea could be to write a story from the perspective of a civilian caught in the middle of the Kaiju battles. Show their fear, their attempts to survive, and how they interact with the military trying to stop the Kaiju. Another could be a story about a Kaiju that has unique abilities not seen in the original lore, and how it changes the dynamic of the wars. Maybe it could be a Kaiju that can communicate with humans and tries to form an alliance against the more destructive Kaiju.
One idea could be a story about a group of survivors who find an ancient weapon that might be able to defeat the Kaiju. They then have to embark on a dangerous journey to figure out how to use it.
In Naruto Kaiju Bloodline fanfiction, an interesting plot could be that the main character with the Kaiju bloodline is ostracized by the village at first. But as time goes on, they prove their worth when a massive, Kaiju - like enemy attacks. Their ability to understand the nature of the Kaiju allows them to find its weakness and defeat it. Additionally, there could be a sub - plot about the main character trying to find others with the same bloodline to form a sort of 'Kaiju Clan' within the village for mutual support and to share their knowledge of their unique powers.
One popular 'kaiju x kaiju fanfic' story could be about Godzilla and Mothra forming an alliance in a unique way. Maybe they team up against a new, more powerful enemy that threatens their world.
Perhaps a story where a baby Kaiju is accidentally transported to a different dimension. In this dimension, it's the only Kaiju, and it has to adapt to a completely new environment. Meanwhile, the humans in the Pacific Rim world are trying to find a way to bring it back, not knowing how it will have changed in this strange new place.
One well - known kaiju origin story is Godzilla. Godzilla was created as a result of nuclear radiation. The nuclear tests in the Pacific Ocean awakened this giant prehistoric creature. It was a metaphor for the destructive power of nuclear weapons.