Luffy uses Gear 5 in a significant battle towards the later part of the manga. But the exact chapter or arc can vary depending on how you're reading it.
I think it's in a relatively recent chapter, but the exact one might vary depending on where you're reading the manga. You might need to check the latest updates.
Well, in the fanfiction, Gear 4 Luffy might have had some new and unexpected interactions. Maybe he could have teamed up with some other pirates in a different way. Since he was in such a powerful form, he could have inspired more of the pirates to fight back more bravely against the Marines. And his presence in Gear 4 could have also affected the admirals' strategies, making them more cautious or forcing them to use their more powerful techniques earlier.
It would likely make the storyline more exciting. Gear 4 Luffy is extremely powerful, so his presence in Marineford would change the power dynamics. He could defeat more enemies quickly.
When we talk about'reacting to fanfic', it's a broad concept. It can be a very personal experience. Some people might react with enthusiasm, sharing the fanfic widely because they love how the author has reimagined the story. Others might react more critically, perhaps pointing out inaccuracies in the portrayal of the original elements. And then there are those who might have an emotional reaction, like getting really attached to a new character introduced in the fanfic or being moved by a particular scene in the story.
First, just read the fanfic carefully. Then, you can start by noting down your initial feelings, like whether you liked it or not. For example, if it made you laugh right away, that's a good starting point for your reaction.
They could be amused. Maybe the fanfiction has some really funny and out - there ideas that the RWBY characters haven't thought of before, like a new type of Grimm created just for the fanfic.