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.
In this fanfiction, Goku vs Jiren is likely to be an epic battle. Goku's power with the Universe's Watch might bring new and unexpected abilities. Jiren, on the other hand, is an extremely powerful opponent. The fight could involve intense energy blasts, high - speed combat, and strategic maneuvers. It might also explore the growth of Goku's character and his newfound power in relation to Jiren's unwavering strength.
In the fanfiction, the plot could develop such that the power of the universe's watch attracts other villains or powerful beings. They might try to steal the watch from Goku during his battle with Jiren. This would add a new layer of complexity as Goku has to fend off these new threats while still trying to defeat Jiren.
One interesting plotline could be Deku having to face off against his classmates in a series of challenges that test not only their quirks but also their teamwork and strategic thinking. Maybe there's a misunderstanding that leads to the conflict.
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.
Deku himself is likely to shine. Given his powerful quirk and his growth throughout the main series, he'll surely put up a great fight against his classmates. Bakugo could also shine as he's always been in competition with Deku and has a very strong quirk.
One interesting aspect could be the different interpretations of the characters' powers. In fanfiction, the author might explore new ways Deku uses his One for All ability against Overhaul's powers. It can also show different battle strategies that might not be in the original manga or anime.
You can try looking on fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. These platforms usually have a wide variety of fanfictions, including ones related to 'Deku vs Overhaul'. Just use their search functions to find what you're looking for.