Well, one possible future for them in Marine fanfiction could be that they form a special unit. Ace with his fire power, Luffy with his rubber abilities and Sabo with his skills would be a formidable team. They could be sent on special missions to deal with the toughest pirates. This way, they are still following their dreams of adventure while being part of the Marines.
In some fanfictions, female Luffy might be portrayed as having the same adventurous spirit as the original male Luffy. She could be fearless in the face of danger and always eager to explore the Grand Line. However, being a female in the Marines' world might bring some unique challenges. For example, she may have to deal with more discrimination in a male - dominated organization like the Marines. But she would still hold onto her dreams and values, just like the Luffy we know.
The idea of Ace, Luffy, and Sabo in the Marines is quite interesting. They could use their bonds to make the Marines a more family - like organization. Their unique abilities would also give them an edge. For instance, Luffy's stretching powers could be used in creative ways during rescue missions or combat.
One common plot line is female Luffy rising through the ranks of the Marines. Despite the challenges and prejudices she faces as a female, she uses her strength and determination to prove herself. Another plot could be her encountering pirates and having to make difficult decisions. For instance, if she comes across old friends who have become pirates, she has to choose between her loyalty to the Marines and her personal feelings.
A marine who has a special ability or talent that the crew lacks. Maybe a marine who is really good at deciphering ancient texts or has a unique form of martial arts. They would be attracted to Luffy's crew because of their freedom - loving spirit. And once they join, they could use their skills to help the crew in their adventures, whether it's finding a hidden treasure or fighting against a powerful enemy.
I think it has the potential to be very engaging. A marine joining Luffy's crew would bring in a clash of ideologies and force both the marine and the crew to adapt and grow. It could lead to some unexpected plot twists and character developments.
If a marine joins Luffy's crew in a fanfic, it could be quite interesting. At first, there might be a lot of distrust among the crew members. After all, they've been fighting against marines for a long time. But if the marine has a strong sense of justice that aligns with Luffy's own view of right and wrong, they could gradually be accepted. For example, the marine might bring in some new combat techniques or knowledge about the navy's operations that could be useful to the Straw Hats.
One great 'tails and marine' fanfiction could be 'The Adventures of Tails in the Marine World'. It has an interesting plot where Tails discovers a hidden underwater civilization. He uses his mechanical skills to help the marine creatures there, which makes for an exciting read.
Well, a fanfiction involving Naruto and a Rogue Marine could be really interesting. Maybe the Rogue Marine could be from a different world and end up in the Naruto universe. They could have unique powers that would either clash or work well with the ninja abilities in Naruto. For example, the Marine's use of guns and advanced technology might be a new threat or a useful tool in the Naruto world.