Well, in some One Piece Law fanfiction, there are concepts about Law's devil fruit powers. Writers might come up with new and creative ways he can use the Ope - Ope no Mi. For example, not just for medical purposes or combat, but perhaps for some unique forms of transportation or even creating alternate dimensions within his Room ability.
Another concept is Law's role in the overall One Piece world. Fanfiction might explore what would happen if Law took on a more prominent leadership role in the pirate world. He could be the one to bring about a major change in the power balance between the Yonko, the World Government, and the pirates. This could involve him making strategic alliances with other pirates or finding ways to expose the secrets of the World Government.
One interesting concept is alternate universe stories. For example, what if Luffy didn't eat the Gum - Gum Fruit but a different Devil Fruit? Another concept could be character backstories that are expanded or changed. Maybe a fanfic delves deeper into Sanji's time at the Baratie and creates new relationships or events during that period. Also, there are fanfictions that explore different power - up scenarios for the characters, like if Zoro found a new type of sword with unique abilities.
One interesting concept is a crossover with other popular anime like Naruto. Imagine Luffy and Naruto teaming up, it would be a clash of two very different power systems and personalities. Another concept could be a crossover with a superhero universe. For example, Luffy meeting Superman. Their powers are so different, it would make for an exciting story.
In some One Piece gamer fanfiction, there's the concept of 'cheat codes'. These could be things like a secret knowledge that allows a character to instantly learn a new Haki technique or unlock a hidden island full of treasures. Also, the idea of character customization is popular. So, a fanfic might explore how Luffy could customize his straw hat or add new abilities to it, like making it a shield or a weapon enhancer.
In some One Piece marine fanfiction, there are concepts about marine - pirate alliances in secret. This goes against the normal narrative but creates a really interesting dynamic, as it makes you wonder about the possible reasons behind such alliances, like mutual benefits in a particular situation or a hidden agenda that might be beneficial for both parties in the long run.
One interesting concept could be the idea of Pokemon existing in the One Piece world. For example, trainers in the Straw Hat crew. Luffy might befriend a really strong and unique Pokemon, like a Pikachu with a Conqueror's Haki ability. It would add a whole new dynamic to their adventures as they explore the Grand Line.
In 'one piece si fanfiction', one interesting concept could be alternate character backstories. For example, giving more in - depth details about a minor character's past that was only hinted at in the original 'One Piece'.
One interesting concept could be the role reversals in relationships. For example, if Zoro was genderbent, how would her relationship with Sanji change? Maybe instead of the usual banter, there could be a more complex dynamic with different types of flirting or rivalry. Another concept is how the character's appearances would change. A genderbent Nami might have different fashion choices that still reflect her love for money and treasure, like wearing more elaborate and expensive - looking outfits. Also, their fighting styles could be adapted. A female Luffy might use her agility in different ways compared to the original male Luffy, while still maintaining that indomitable spirit.
Well, in One Piece system fanfiction, a common concept is the creation of new Devil Fruits. Imagine a Devil Fruit that gives the user the ability to control time in a limited way. This could completely change the power dynamics in battles. Also, some fanfictions explore different alliances among the characters. For instance, Zoro and Sanji might form a temporary alliance with a new character to take on a powerful enemy that they couldn't defeat alone.
One interesting concept could be a character being reborn with knowledge of future events in the One Piece world. For example, they might know about the true nature of the One Piece treasure before the main characters do, which could lead to a whole new set of adventures and interactions. Another concept could be a reborn character having a different Devil Fruit ability than in their previous life, changing the power dynamics in the story.
One interesting concept could be the reincarnation of a character into a different era in the One Piece world. For example, a character from the past reincarnating during the Straw Hats' time. This could lead to unique interactions and plot developments as they might have knowledge from their past life that could change the course of events. Another concept could be the reincarnation of a powerful villain, but with a different personality or goal, which would add a new layer of complexity to the story.