One way to integrate them is by exploring similar themes. All three have elements of heroism and facing great challenges. The Shinju represents a powerful and often dangerous force in Naruto. In Batman's world, there are powerful villains. A fanfiction could bring these together by having Batman face a threat related to the Shinju, with help from Naruto characters. They could also explore the different concepts of justice in both universes.
The 'naruto shinju fanfiction' is appealing because it allows fans to expand on the existing Naruto world. With the Shinju as a central element, there are countless possibilities for new relationships between characters, new conflicts, and new adventures. For example, stories can explore how the Shinju's power could be harnessed for good or evil, and how different characters would react to it.
I'm not entirely sure about the specific plot of this fanfiction as there could be many different interpretations and versions. It might involve some new adventures of Naruto related to the Shinju and a goddess figure, perhaps with new powers, challenges, and character interactions.
A possible crossover could involve the corruption aspect. The Shinju in Naruto has been associated with negative forces and power - hungry individuals. In Gotham, there is also a lot of corruption. Batman is constantly fighting against it. A fanfiction could show how the Shinju's influence might seep into Gotham, corrupting some of its inhabitants, and how Batman tries to stop this new form of evil. He might even have to team up with Naruto characters who understand the Shinju better to save the city.
One way to blend them is through crossovers. For example, imagine Naruto characters in the Marvel universe facing off against villains. The shinju could be a powerful, other - worldly entity in this new setting. Naruto's ninjutsu skills could be compared to the powers of Marvel superheroes. Maybe the shinju's power could be harnessed by a villain, and Naruto and his friends, along with some Marvel heroes, have to stop it.
Since it's a Naruto - related fanfiction, Naruto is likely to be one of the main characters. And considering the title, the goddess would also be a main character. There might also be other Naruto characters like Sasuke or Sakura who could be involved depending on how the story unfolds.
One interesting concept could be the origin of the Shinju Tree. Maybe it has a deeper connection to an ancient civilization in the Naruto universe that was lost. Another could be the power it holds and how different characters interact with it in unique ways, like a character trying to use its power for good instead of the evil intentions it was often associated with in the original story.
One interesting concept could be the unique powers that the Shinju fruit bestows. It might give the user abilities related to nature manipulation on a grand scale, like controlling all forms of plant life in the Naruto universe. Another concept could be the impact it has on the character's chakra system, perhaps enhancing it in ways not seen before.
In some fanfictions, Kushina was sealed into Naruto through a complex jutsu. It might be a modified version of the sealing jutsu used to seal the Nine - Tails. The process could involve special incantations and chakra manipulations.
Well, in some Naruto fanfictions, Bardock might be sealed by powerful jutsu. Maybe a dark ninja uses a forbidden sealing technique to lock him away, preventing him from interfering with their evil plans.