One plot idea could be that the OC is a spirit from a different part of the spirit world who comes to Yubaba's bathhouse. Haku is immediately intrigued by this new spirit and they start to form a bond as they both deal with the chaos in the bathhouse. Another idea is that the OC has a special power that can help Haku break free from Yubaba's control, leading to a journey of self - discovery for both of them.
Well, there could be a plot where the OC is an artist who gets lost in the spirit world. Haku is drawn to the OC's creativity and the way she sees the spirit world in a different light. They start to create art together, using the unique elements of the spirit world. This art then becomes a powerful force that changes the balance in the spirit world, for better or for worse. And throughout this process, their relationship blossoms as they face the challenges that come with their new - found power.
A really interesting plot could be where the OC is a human who has a connection to the spirit world from birth. She enters the spirit world and meets Haku. As they get to know each other, they realize that their fates are intertwined in a way that goes back generations. The OC then has to fight against the rules of the spirit world to be with Haku. This would involve a lot of drama and exploration of the spirit world's rules and mysteries. It could also include some epic battles against other spirits who oppose their relationship.
One idea could be a story about Haku and Chihiro reuniting in the spirit world years later. Chihiro has grown up but still remembers Haku vividly. Another could be a fanfiction where they go on an adventure together outside of the bathhouse to explore other parts of the spirit realm that were previously unknown to them.
One idea is that Chihiro gets trapped in a different part of the spirit world and Haku has to use all his powers to find her. Along the way, he realizes just how much she means to him.
Yes, Fanfiction.net also has a good selection. Look for ones with high ratings and a lot of reviews. A common theme in these fanfictions is the OC helping Haku remember his true identity while falling in love with him. The writers usually describe the spirit world in great detail, making it an immersive experience for the readers as the Haku x OC relationship unfolds.
One idea could be a fanfiction that focuses on what happened to Haku after Chihiro left the spirit world. Maybe he had to face new challenges or make difficult choices. Another could be a story about Chihiro returning to the spirit world as an adult, but finding it completely changed. And a third idea could be a fanfiction that delves into the backstories of the minor spirits we saw in the movie, like the soot sprites and how they came to be in the bathhouse.
A fanfic could focus on a journey that Haku and Chihiro take together within the spirit world that they didn't get to do in the movie. They could face new challenges and in the process, their relationship deepens as they rely on each other for support.
One great fanfic could be 'Chihiro and Haku's New Adventure'. It might explore their relationship further after the events of the movie, like them exploring new parts of the spirit world together.
In this fanfiction, Haku might be searching for a way to bring some of the beauty of the human world back to the spirit world. He travels across different cities, seeing various forms of art, architecture, and nature. Along the way, he meets a botanist who teaches him about plants. Haku then decides to try and create a garden in the spirit world inspired by what he has seen in the human world. He faces many challenges in transporting the plants and knowledge, but with his determination, he tries his best to make it happen.
One idea could be a crossover with 'Alice in Wonderland'. Chihiro could find herself in Wonderland and have to navigate through the strange rules and characters there, while also using her experiences from the Spirit World. Maybe she'd meet the Cheshire Cat who could be as mischievous as some of the spirits she met in Spirited Away.
One possibility could be that Haku, having finally found a way to the human world, tries to adapt to modern life. He might struggle with things like technology. For example, he could be fascinated by cars but also a bit scared of them at first. He would also have to deal with the different social norms in the human world. Maybe he would make a human friend who helps him understand the world better.
Their relationship could be developed by having them communicate more deeply. For example, Haku could share more about his past and his true form with Chihiro. This would create a stronger bond between them as Chihiro would understand him better.