A different approach could be a fanfic where Nico Robin discovers she's pregnant first, and Nami later. Robin could be more calm and collected about it initially, while Nami is a bit more panicked. But as time goes on, they both grow into their new roles as future mothers. The story could also explore how their pregnancies change their relationships with the other crew members and their own personal goals.
To write a great fanfic, start with a strong plot. Maybe there's a prophecy about their children being very important in the One Piece world. This would add an interesting layer to the pregnancy story. Develop the relationships between the characters well. Show how the other Straw Hats interact with Robin and Nami during this time. And don't forget about the details. Describe how they might decorate a nursery on the ship or what kind of baby clothes they'd get.
Yes, there are likely many fanfics that focus on their adventures without involving pregnancy. For example, there could be ones about them exploring new islands, facing powerful enemies together, or uncovering ancient secrets. These types of fanfics would center more on the action and camaraderie aspects of their relationships.
Maybe the OC is from a long - lost island with unique knowledge. Robin is interested in the historical aspects of this knowledge and Nami sees the potential for great treasures. The OC then has to deal with the different personalities of Robin and Nami. Robin is calm and intellectual, while Nami can be feisty. Their interactions lead to a series of adventures and a deepening of their relationships.
For the OC, give them a distinct personality trait. For example, if they are overly curious, it can lead to interesting interactions with Robin's love for knowledge and Nami's practicality. Show their growth over time, like learning from Robin's wisdom and Nami's street - smart ways.
One idea could be that the OC is a new pirate who joins the Straw Hats. Over time, they develop a special bond with Nico Robin due to their shared interest in ancient history. Meanwhile, during an encounter with Boa Hancock, the OC manages to gain her respect in an unexpected way, like saving her from a new threat in the Grand Line. This could lead to a complex love triangle where the OC has to navigate their feelings for both strong - willed women.
One popular scenario is them competing in a pirate - themed tournament on an island. They would show off their skills and compete against other pirates. Another could be them having to solve a mystery on a haunted ship, where they use their wits and powers to figure things out.
Adventure is a very common theme. Since Nami and Robin are part of the Straw Hat crew in One Piece, many fanfictions involve the OC joining them on their adventures in the Grand Line. For example, they might go on a quest for a lost treasure or to discover a new island.
There's a fanfic called 'Fateful Encounters'. In this story, the OC meets Nami and Robin in a rather unexpected situation in a bustling port town. The author does a wonderful job of developing the relationships gradually. As the story progresses, they embark on a journey to find a hidden treasure, and throughout the adventure, the bond between the OC, Nami, and Robin deepens.
One interesting plot idea could be that they go on a special adventure to find a lost ancient island that only Robin can decipher the clues to reach. And along the way, Luffy's unwavering determination and Robin's knowledge work together to overcome various obstacles like strange sea creatures and difficult terrains.
One idea could be a story where Luffy, Nami and Robin get stranded on a mysterious island. Luffy is eager to explore, Nami is worried about resources and Robin is interested in the island's history. They work together, with Luffy's leadership, Nami's navigation skills and Robin's knowledge to survive and find a way off the island.