It starts at a specific point in the manga, but I can't recall exactly without looking it up. You might want to check some manga forums or dedicated fan sites for the precise chapter.
It's hard to say for sure. Both Sukuna and Gojo are incredibly powerful, and it could depend on various factors like their current state and the circumstances of the fight.
A good Spiderman vs Batman reaction fanfiction should have well - developed characters. It should stay true to the essence of both characters. For example, Spiderman's quippy nature and Batman's brooding seriousness. The plot should be engaging, not just a simple fight. Maybe there could be a misunderstanding that leads to the conflict. And the setting can add a lot to the story too. If it's set in a shared universe where both heroes have to deal with new threats while also facing each other, that could be really interesting.
I think Spiderman would have an edge in a fight against Batman. His powers are more innate. He can swing from building to building effortlessly and has a much stronger physical strength compared to Batman. Batman is just a human, albeit a very well - trained one. In the fanfiction world, though, the story could be twisted to make Batman's gadgets and strategic mind overpower Spiderman. But overall, Spiderman's natural abilities give him an upper hand.
Sukuna does die in the manga. The way it happens is quite dramatic and ties in with many other elements of the story, adding depth and tension to the overall narrative.