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 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.
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.
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.
One Piece Luffy and Nami were one of the main characters in One Piece. Luffy was a brave and adventurous boy. His dream was to become One Piece, find the legendary One Piece, and become the most powerful pirate in the world. As for Nami, she was a female character with the ability of a genius navigator. Her dream was to find her " Goddess of the Sea " Robin and protect her from any danger.
Luffy and Nami played a very important role in the story, and their relationship was very rich. In the story, Luffy met Nami in an adventure and began their adventure. Although they often faced various dangers and difficulties, they had always supported and encouraged each other, becoming inseparable partners.
Luffy would probably be super excited. He's always been on this big adventure, and meeting his dad would be like a new milestone. He might jump up and down and start asking a million questions right away, like what his dad has been doing all this time and if he has any cool stories from his own adventures.
Luffy Gear 5 Fanfic: In the heart of a new island, Luffy stood tall in his Gear 5 form. His body pulsed with a vibrant red energy as he faced the powerful new foe. 'I won't let you harm my friends!' he roared. With a swift motion, he stretched his arm like a rubber band, then snapped it forward, sending a shockwave of Haki towards the enemy. The foe tried to dodge but was caught in the blast, sent flying backwards. Luffy then bounced around the battlefield, his movements a blur, leaving trails of light as he continued his attack.
In a One Piece fanfic, an OC (Original Character) as Luffy's rival could be really interesting. This OC might have a unique Devil Fruit ability that directly opposes Luffy's powers. For example, if Luffy has the Gum - Gum Fruit which gives him stretchy abilities, the rival could have a hardening or shrinking ability. This would create intense battles between them as they fight for different ideals on the Grand Line.
One popular type of 'One Piece' fanfiction involving Luffy and Dragon might be about their eventual reunion. Since Dragon is Luffy's father, many fans like to imagine the moment when they meet again. In some fanfictions, Dragon could be secretly guiding Luffy's journey without him knowing. This adds an interesting layer of mystery to Luffy's adventures as he is unknowingly following a path his father has some influence over.
One possible fanfiction could be about Zoro and Luffy's unwavering loyalty to each other. Zoro is always there to protect Luffy and vice versa. They might face a powerful enemy that tests their bond, and through their combined strength and trust, they emerge victorious.