A theme that often comes up is his physical pain and how he endures it. This can be used to show his strength and tenacity. For example, in a battle - themed fanfiction, he endures great pain but still manages to fight for the sake of his village. Also, the theme of self - discovery through pain is common. As he experiences pain, he learns more about himself and his limits.
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.
The theme of sacrifice could also be present. Both characters are willing to sacrifice for their causes. In the context of a yaoi fanfiction, this could translate into sacrifices for each other. For example, Pain might sacrifice his original plans for world domination for Kakashi, or Kakashi might put his village - related duties on hold to be with Pain, exploring the lengths they would go for their relationship.
Another possible fanfiction could be centered around Kakashi's pain from his past traumas, like the loss of his father. It could show how these past experiences resurface when he faces a new threat in the village. The story could detail how he overcomes this pain by finally coming to terms with his past and using it as a source of strength.
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.
Minato might also be a prominent character. As their teacher, he can influence the way Obito and Kakashi interact. In some fan fictions, he could be the one to help them resolve their differences or provide some crucial information about their past that changes their current situation.
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.
It's hard to say for sure. If the fanfiction focuses on Hinata's growth, she could potentially defeat Pain through her own skills and some unexpected twists. But Naruto is also likely to be a major factor, so it could be a combined effort of both of them that overcomes Pain.
In this fanfiction, Naruto might be extremely enraged seeing Hinata in danger against Pain. Hinata, on the other hand, would likely show her newfound strength and determination. Maybe she'd manage to land a few surprise attacks on Pain before Naruto fully jumps into the fray.