There probably is. Fanfiction is a vast world where all kinds of ideas are explored. Since Naruto and Jiren are from different anime universes, a fanfiction about Naruto being a fan of Jiren could be really interesting. It might involve Naruto somehow learning about Jiren's power and being in awe of it. Writers could play around with different scenarios like Naruto trying to train like Jiren or even seeking his advice in the fanfiction world.
One possible plot could be that Naruto, through some sort of interdimensional rift, witnesses Jiren's power during the Tournament of Power. He becomes so impressed that he starts to study Jiren's fighting style and tries to incorporate it into his own ninja techniques. This could lead to Naruto facing some resistance from his friends and teachers who don't understand his new fascination, but Naruto persists in his pursuit to become stronger like Jiren.
Yes, there are some. In some fanfictions, they might start as rivals but gradually develop a deep bond that could be interpreted as love. However, these are often very creative interpretations that deviate from the original animé's more straightforward rivalry theme.
One key element is the near - extinction of his race. This event had a profound impact on him and motivated his pursuit of strength. Another is his membership in the Pride Troopers, which shaped his fighting style and his sense of justice. Also, the destruction he witnessed in his youth is an important part of his back story.
Jiren is a powerful warrior from Universe 11 in Dragon Ball Super. His back story is centered around his quest for justice and strength. He comes from a race that was nearly wiped out. This tragic event in his past made him determined to become stronger so that he could protect what was left. He trained rigorously under the Pride Troopers and became one of the strongest beings in the multiverse. His sense of justice is unwavering, and he believes that true strength should be used to uphold order and protect the innocent.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions from various fandoms, including Dragon Ball where Goku and Jiren are from. Just use the search function and type in relevant keywords like 'Goku Jiren love' and you might find some interesting reads.
Saitama would win. He has shown incredible strength with just one punch. His power seems limitless, and in a fanfiction scenario, his simplicity and raw power would likely overpower Jiren's more complex abilities.
One possible plot twist could be that Jiren discovers a way to nullify Saitama's strength. Maybe he finds some sort of energy - draining technique that weakens Saitama over time. Another could be that Saitama holds back for some reason, like he wants to see the full extent of Jiren's power, and in doing so, he gets into a real struggle.