A more complex plot could be that the OC is on a mission to find a lost treasure. Hancock, believing there might be something in it for her island, decides to team up with the OC. Along the way, they face many challenges together and their relationship develops from mutual interest to deep love.
One idea could be that the OC is a lost traveler who washes up on Hancock's island. Hancock initially views the OC with suspicion but as time passes, she starts to see his unique qualities. Maybe the OC has some special knowledge about the outside world that intrigues Hancock.
One idea could be that the Fem OC is a new pirate who arrives on Hancock's island. At first, Hancock is wary but as they interact, they find common ground in their strength and independence. Maybe the OC has a special ability that Hancock respects. Another plot could involve a threat to Hancock's kingdom, and the Fem OC helps her defend it, leading to a deepening of their relationship.
One idea could be that Hancock's feelings for Luffy lead her to secretly help the Straw Hats in a dangerous situation. For example, when they are facing a powerful enemy on an island, Hancock uses her influence and powers to divert the enemy's attention.
Another plot could involve a common enemy. Maybe a new powerful pirate group attacks both Amazon Lily and Fem Luffy's friends. Hancock and Fem Luffy have to work together to defend. During the battle, Hancock realizes Fem Luffy's strength and leadership skills, and they gradually fall in love as they fight side by side. After the battle, they start to explore their relationship more deeply.
A more light - hearted plot could be that the OC is a clumsy but kind - hearted person who accidentally stumbles into Hancock's life. Despite Hancock's initial aloofness, the OC's genuine nature slowly breaks down her walls. They go on various adventures together on the island, and the OC helps Hancock see the world in a different, more positive light.
Well, a great plot might be that the OC is an artist who can draw the secrets of the Poneglyphs without actually reading them. Robin is fascinated by this ability and they work together to uncover the true history of the world. Also, perhaps the OC has a connection to Robin's past, like knowing someone who was important to her family, which creates an emotional bond between them.
A great plot idea could be that the OC is a healer who saves Ace's life after a particularly brutal fight. Ace is initially distrustful but as he recovers, he sees the kindness in the OC. They then go on a journey to find a rare herb that can cure a disease that is spreading among the pirates, and along the way, their relationship blossoms.
Start with small interactions. For example, the OC could accidentally save one of Hancock's pets or help with a small task on the island. This would make Hancock notice the OC in a positive light.
One great fanfic could be 'Luffy and Hancock's Grand Adventure'. It might explore their relationship in a new and exciting way, perhaps with them going on a quest together that deepens their bond. Another could be 'Luffy's Surprise Encounter with Hancock' which could focus on a chance meeting that changes their dynamic.
One idea could be that the OC is a long - lost relative of a Straw Hat member. For example, an OC who is related to Luffy and has a unique power of their own, like the ability to control the weather in a small area. This could lead to interesting storylines where the OC helps the crew during difficult battles or in traversing dangerous seas.
The OC could be a pirate from a rival crew. They meet Kid during a battle. Instead of fighting to the death, they end up in a situation where they have to team up against a greater enemy. During this time, they get to know each other better, and a relationship between Kid and the OC starts to form.