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.
In the fanfic, their relationship could develop in a rather magical way. Haku, being a spirit, has a different view of the world compared to Chihiro. But as they interact more, they start to see things from each other's perspective. Maybe they start with simple exchanges like sharing a meal in the spirit world. Then, as time passes, they find themselves drawn to each other. Haku might show Chihiro secret places in the spirit world, and these shared experiences make their bond stronger. Eventually, they develop a love that's both pure and powerful, full of little affectionate moments like stolen glances and gentle touches.
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.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of fan - created works, and you're likely to find many Spirited Away fanfics there, including ones about Chihiro and Haku.
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 possible plot could be that Haku and Chihiro meet again in the spirit world years after Chihiro's first visit. As they reunite, they start to explore their feelings for each other more deeply. They go on adventures together, facing new spirits and challenges, and their relationship gradually blossoms into a romantic one filled with tender moments and mutual understanding.
One possible plot could be that the kiss is a moment of realization for both Chihiro and Haku. It might be a way for them to break a spell that has been holding Haku in some sort of limbo. After the kiss, Haku could start to remember more of his true self and his past, which could lead to him being able to finally leave the spirit world and find peace. And for Chihiro, it could be a sign of her growing up and understanding her feelings in this strange world she has found herself in.
It could add a romantic element that changes the dynamic between the characters. Instead of just being friends or allies, it makes their relationship more complex. This could influence how they interact with other spirits in the story. For example, some spirits might be more accepting while others could be jealous or against it.
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.
I'm not entirely sure if there is a specific fanfiction about Haku and Chihiro getting pregnant. While Spirited Away has a huge fan base and a lot of fan - created content, this particular topic might be a bit controversial as it goes against the rather innocent and magical nature of the original film. But it's always possible that in the corners of the fanfiction community, someone has explored this idea. You may need to dig deep into the search engines dedicated to fanfiction to find out.