One Piece: The Heart of the Sword Hero was a Japanese manga created by Oda Suichiro. It told the adventures of the protagonist, Monchi D. Luffy, before he became a Pirate King.
The manga was loved by the majority of readers and was hailed as a classic in the Japanese manga world. The story was rich and the characters were vivid, so it was very readable and interesting.
If you're interested in adventure stories, then One Piece: Heart of the Sword Hero might be a good choice. However, whether it looks good or not is up to you to decide.
One common theme is adventure. Since it's set in the One Piece world, the OC and Thatch often go on adventures together. Another theme could be love and friendship, as their relationship is explored.
Common themes include exploration. The OC explores not only the physical world of One Piece but also the complex relationships in the harem. Cultural differences can be another theme. The OC might come from a different background and has to adapt to the unique cultures in One Piece. And finally, the theme of loyalty. The OC has to show loyalty to the harem members and vice versa for the relationships to work.
A great plot could be that the OC is a doctor with a mysterious past. Hina gets injured during a battle and the OC is the only one who can save her. As the OC nurses Hina back to health, they start to have long conversations. The OC tells Hina about different cultures and places in the One Piece world that she has never heard of. This makes Hina see the world in a new light, and she starts to fall for the OC's knowledge and kind heart.
First, focus on the relationship between Shirahoshi and the OC. Decide if it's a friendship, a mentorship, or something more romantic. For example, if it's a friendship, they could have adventures together exploring the underwater world. Second, introduce a conflict. It could be something like an evil pirate group threatening Fish - Man Island or a misunderstanding within the fish - man society about the OC. Third, let the characters grow. Shirahoshi might become more confident with the OC's support, and the OC could learn about the importance of protecting the ocean and its inhabitants.
One idea could be that the male OC is a former slave who was freed by Whitebeard. He has a deep sense of loyalty towards Whitebeard and is always ready to fight for his newfound family. His unique ability could be related to some form of water - based combat, which is rare in the One Piece world.
One possible storyline could be that the OC is a wandering adventurer who saves Princess Vivi from a new threat in Alabasta. They then team up to discover the source of this threat which turns out to be an old enemy of the kingdom who has returned with a new power. As they journey together, they develop a deep friendship and respect for each other.
One good 'One Piece Zoro x OC fanfiction' is 'Swords and Promises'. It has a well - developed OC who joins the Straw Hats and forms a special bond with Zoro. The story is full of adventure and their relationship gradually evolves from mutual respect to something deeper.
One possible plot could be that the OC is a new pirate in the One Piece world and meets Hina during an island stop. They start off as rivals, constantly trying to outdo each other in various tasks like treasure hunting or helping the local villagers. But as time goes on, they realize they have more in common than they thought and develop a deep friendship that could potentially turn into something more.
One good 'One Piece Harem x OC Fanfiction' is 'A New Adventure in One Piece World with OC'. It has an interesting plot where the OC character has unique interactions with the One Piece characters in a harem - like setting. Another one could be 'OC's Journey in the One Piece Harem'. These fanfictions often explore different relationships and character developments that are not in the original story.