Some characters might be worried. They could see Gear 5 as a sign of Luffy taking on too much risk. Since it's a very extreme form, it might put him in more danger than before. For example, his crewmates might fear for his safety as he battles with such a powerful transformation.
There could also be characters who are inspired. Luffy's Gear 5 represents a new level of strength and determination. In the fanfiction, younger characters or those who look up to Luffy might see his Gear 5 and be motivated to become stronger themselves, training harder to reach new heights.
They might be shocked. Luffy's Gear 5 is such a powerful and strange form. In the fanfiction, characters could be amazed at his new abilities, like his cartoon - like movements and seemingly limitless power.
I think Shanks would have an interesting reaction. He has known Luffy since he was a kid. Seeing Luffy reach Gear 5, he would probably be proud but also a bit cautious. He might think about how far Luffy has come and also wonder what challenges this new power will bring for Luffy and the world at large.
In some One Piece Luffy Gear 5 fanfiction, there could be the idea of Luffy sharing his Gear 5 power with his crewmates temporarily. This would not only make for some cool team - up attacks but also show the deep bond within the Straw Hat crew. Also, a fanfiction might explore how Luffy's Gear 5 affects his relationship with other pirates or the World Government. Maybe it makes him an even bigger target or maybe it causes some pirates to want to ally with him out of fear or respect.
In fanfiction, Luffy's character in Gear 5 might develop a greater sense of responsibility. Since Gear 5 is so powerful, he realizes he has to be more careful about using it. For example, he might avoid using it in areas where there are a lot of innocent bystanders.
Another storyline could involve a female Luffy's relationships with other female characters in the One Piece world. She could form a strong sisterhood with Nami and Robin, and together they could take on challenges that are specific to women in the pirate world. Maybe they fight against a group that discriminates against female pirates.
They might be shocked. Luffy has so many wild and dangerous adventures in his memories. His friends would probably be in awe of how much he has endured and how strong his will is.
For Luffy, he might develop a deeper understanding of history and knowledge through his interactions with Robin. He could become more patient when it comes to listening to Robin's long - winded explanations about ancient texts. For Robin, she could become more open and trusting of the crew, especially Luffy. His unwavering loyalty towards her could make her feel more at home on the ship.
In One Piece bounty fanfiction, reactions can vary greatly. Characters might be shocked when seeing a new high bounty. For example, when Luffy's bounty goes up, his crewmates could have a mix of pride and worry. Zoro might smirk, proud of his captain's growing reputation, while Nami could be worried about the increased danger it brings to the crew.
If Luffy was kidnapped in a fanfiction, his crew would surely go to great lengths to rescue him. Nami would probably come up with a smart plan, using her knowledge of the seas and navigation. Zoro would be ready for a fight, not fearing any opponents in the way. Sanji would keep everyone fed during the rescue mission, while also being prepared to kick some kidnapper butts with his powerful kicks.
Luffy would be the central figure. His relationship with Vivi is one of friendship and mutual respect. In the context of a harem, Luffy might not fully understand the concept at first. Vivi, on the other hand, could act as a mediator or an equal partner among the female characters in the harem. The harem members could all be united by their admiration for Luffy and his noble goals.
There could be a plotline where they get transported to a different dimension. In this new world, Zoro has to learn new sword techniques to fight the strange creatures. Sanji discovers new ingredients and has to adapt his cooking. Luffy befriends some of the locals and together they figure out a way to get back to their own world.