Law's personality could become more open. With the Straw Hats, there's a sense of family and trust. Law, who has been more of a lone wolf in a way, would start to open up about his past, his dreams, and his fears. He would be influenced by the Straw Hats' unwavering loyalty to each other. He might even become more optimistic, as the Straw Hats always seem to find a way out of tough situations with their positive attitudes.
He might become more relaxed. The Straw Hats are a very laid - back and fun - loving crew compared to Law's more serious group. So, being around them, Law could start to crack jokes more often and not be so uptight all the time. For example, he might start to participate in Usopp and Luffy's silly games on the ship.
His personality would become more outgoing and adventurous. The Straw Hats' lifestyle is full of exploration, so Naruto would be more eager to take risks.
Well, it could be really interesting. There would probably be a lot of initial distrust from the Straw Hats, since they are usually against the Marines. But if the OC has a good heart and a strong reason for leaving the Marines, like disagreeing with their corrupt ways, the Straw Hats might gradually accept them. The OC could bring in some unique skills and knowledge about the Marines' operations, which could be useful for the crew in various situations, like getting out of tight spots when facing other Marine forces.
Well, he'd bring his unique ninja skills. His shadow clone jutsu could be super useful for various tasks on the ship, like handling multiple chores at once. And his rasengan could be a powerful attack against any strong enemies they face. Also, his never - give - up attitude would fit right in with the Straw Hats' spirit.
Naruto is known for his loyalty and determination. If he joins the Straw Hats in fanfiction, these traits would strengthen the crew's unity. His loyalty would mean he'd always have the backs of his new pirate friends, and his determination would inspire them to keep pushing forward, especially in the face of difficult challenges. For example, when they encounter a powerful enemy, Naruto's refusal to give up would encourage the Straw Hats to keep fighting no matter what.
His personality might become more guarded. He'd be surrounded by people who are mostly out for themselves or have very different values from him. So, he'd need to be more cautious in showing his true self.
At first, not very well. The Straw Hats have had bad experiences with Marines. They might see the Marine OC as a potential threat. However, if the OC shows that they are different from the typical corrupt Marines, like by helping the crew out of a tough situation right away, they might start to be more accepting.
If Batman joined the League of Assassins in fanfiction, his personality would likely change quite a bit. He'd probably become more cynical. The League's cut - throat environment and their disregard for human life (to an extent) would make him question his own methods of protecting Gotham. He might also become more secretive from his usual allies, as he'd be involved with a very dangerous and secretive organization. He could develop a more ruthless streak, but still hold onto some of his core values deep down, which would cause internal turmoil.
It could be Chopper. Since Chopper is a doctor and Reiju has some medical knowledge, they might bond over sharing medical techniques and treating the crew's injuries. Also, Chopper's kind - hearted nature would make him a great friend for Reiju who might be used to a more cut - throat family environment.
He might become more aggressive in a way. The Cloud Village has a more rough - and - tumble culture, so Naruto could pick up some of that. But he'd still keep his core of kindness. He might be a bit more brash in his decision - making, influenced by the Cloud's more direct approach.
Well, Naruto's ninja skills would blend in an exciting way. His speed and agility from being a ninja would be useful during battles at sea or on islands. The Straw Hats are all about teamwork, and Naruto's experience in team battles in the ninja world would add to that. His Nine - Tails chakra, if he could control it well, might give the Straw Hats an edge in really difficult situations. He could also use his transformation jutsu for undercover work or just for fun with the crew.