In a straight - up fight, Itachi has some very powerful abilities. His genjutsu can be extremely difficult to break out of, and his ninjutsu attacks are strong. But Batman is no slouch. He has fought against some of the most powerful villains in the DC universe. He would study Itachi's moves and try to find a pattern. Batman might also use his wealth to create some sort of countermeasure to Itachi's Sharingan. Overall, it's a very close call and would likely depend on how the writer of the fanfiction wants the story to go.
The 'jiraiya vs pain' in RWBY fanfiction could be a battle of wits as much as a battle of powers. Jiraiya is a very experienced ninja, and Pain has his own ideology - driven powers. In a RWBY setting, the battle could be affected by things like Dust, the special energy source in RWBY. Jiraiya might be confused by this new element at first, while Pain could try to incorporate it into his attacks. It would be a clash of two different power systems and fighting styles.
The biggest difference is the creativity of the fanfiction writers. In the anime, the fight follows a set storyline. But in fanfiction, anything can happen. For example, Naruto could suddenly gain a new power that was never in the anime. It's like a whole new world of possibilities.
One interesting scenario could be a battle in a dark, abandoned cityscape. Itachi's Sharingan abilities would give him an edge in terms of perception and illusions. Batman, on the other hand, would rely on his gadgets and combat skills. He might use smoke bombs to disrupt Itachi's line of sight and then try to get in close with his martial arts. Another scenario could be a mental battle. Itachi is used to psychological warfare, but Batman is also a master of getting into his opponents' heads. Itachi might try to use his genjutsu to break Batman's will, but Batman's strong mental discipline could resist it.
One interesting scenario could be a battle of wits. Itachi is known for his intelligence and Sakura has grown to be a very smart and capable ninja. They might engage in a mental duel where they try to outmaneuver each other with strategic moves and mind games.
Konan could be really interesting. In some fanfictions, she might have a different backstory or motivation that affects the Naruto vs Pain fight. For example, she could be secretly trying to stop Pain from going too far in his destruction of the Leaf Village.
In most traditional interpretations, Itachi would be favored to win due to his long - established reputation as a powerful and feared ninja. But in the realm of fanfiction, the writer can tip the scales in Sakura's favor. For example, if Sakura has mastered some sort of anti - Sharingan technique or has a power - up that nullifies Itachi's main abilities, she could emerge victorious.
I think young Sasuke would have a very intense reaction. He was so consumed by his hatred for Itachi at that young age. A Sasuke vs Itachi fanfiction would be like a trigger for him. He would be eager to see how the fictional fight is portrayed. If Sasuke in the fanfiction is shown as strong, it might fuel his own ego and make him strive even harder to become powerful. However, if the fanfiction shows Itachi as superior, it could enrage him. He might feel that it undermines his own goal of defeating Itachi and he might even want to find the writer to correct their 'wrong' view.
It's really hard to say who would win. Jiraiya has his Sage Mode which gives him enhanced strength, speed, and perception. But Pain has the Rinnegan which allows him to use powerful abilities like the Six Paths techniques. In the RWBY fanfiction context, it might depend on how well they adapt to the RWBY world. If Jiraiya can quickly figure out how to use Dust to his advantage, he might have an edge. But if Pain can use his powers to disrupt the balance of the RWBY world, he could also come out on top.