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.
The outcome in this fanfiction could be a draw. Naruto and Hinata would put up a great fight against Pain. Naruto would be all fired up, using his Rasengan and other ninjutsu. Hinata would be there, protecting Naruto's blind spots with her gentle fist techniques. But Pain is no pushover. His ability to control gravity and rain down destruction could keep Naruto and Hinata at bay, leading to a situation where neither side can fully defeat the other.
One possible plot twist could be that Hinata discovers a new power within herself during the fight against Pain. Maybe she can tap into some ancient Hyuga ability that even she didn't know existed. This new power could turn the tide of the battle and surprise both Naruto and Pain.
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 common theme is redemption. Pain is often depicted as a character who can be redeemed through his interactions with Hinata. For example, Hinata's unwavering belief in the good of people might make Pain question his own actions.
One possible plot is that Pain targets Hinata to get to Naruto. Since Hinata has a special place in Naruto's heart, Pain might think that by hurting her, he can break Naruto. But Hinata shows great courage and Naruto comes to her rescue.
Hinata saving Naruto from Pain in fanfiction can take on many forms. It could be that Hinata has been secretly training and has a new set of abilities that she unleashes to save Naruto. This not only changes the course of the battle but also the dynamics between the characters. Fanfic writers might also add some emotional elements, such as Hinata's inner thoughts and feelings during the rescue. This makes the story more engaging and gives readers a fresh perspective on the Naruto - Hinata relationship.