A lot of fanfics also focus on their shared experiences in the exorcist world. They go through dangerous missions together, and these experiences bring them closer. For example, in some fanfics, they have to fight powerful demons side by side, which strengthens their bond. Additionally, the theme of self - discovery is present. Both Rin and Shiemi learn more about themselves through their interactions with each other.
One common theme is the growth of their relationship. It often starts as a friendship and gradually develops into something more. Another theme is the acceptance of Rin's true nature. Shiemi is often there to support Rin as he comes to terms with his demon heritage.
I really like the fanfic 'Rin and Shiemi: A New Chapter'. It starts off with them going on a mission together. In this story, they have to rely on each other more than ever. It has some really cute moments where Rin tries to protect Shiemi in his own clumsy way, and Shiemi in turn helps Rin understand his powers better.
One common theme is the growth of their relationship. Since Rin is a demon - human hybrid and Shiemi has her own insecurities, their relationship development is often explored. For example, how they learn to trust each other more deeply.
In 'Blue Exorcist Rin fanfic', a very frequent theme is Rin's battle against his inner demons, both literally and figuratively. His journey to master his demonic powers while still remaining true to his human side is often explored. Also, his relationship with the exorcist community, whether it's facing discrimination or finding acceptance among them, is a common theme. Additionally, his friendships, especially with the people he meets at True Cross Academy, are often a big part of the stories.
In non - adult 'rin and shiemi fanfics', a frequent theme could be their cultural differences within the story world. Rin is a bit of an outcast because of his heritage, and Shiemi comes from a different background. Fanfics might play with this, showing how they bridge those gaps. Additionally, the theme of self - discovery could be there. As they interact, they might learn more about themselves and their own potential, which in turn affects their relationship.
The theme of sacrifice also sometimes appears. They might be in a situation where one has to sacrifice something for the other's well - being or for the greater good. This could add a lot of drama and depth to their relationship. For example, Rin might be willing to sacrifice his position in the exorcist world to protect Shiemi from danger.
One common theme is Rin's struggle with his identity as a half - demon. In many fanfics, his depression stems from feeling like he doesn't belong in either the human or demon world. Another theme could be his relationship with his brother. If there are unresolved issues or misunderstandings between them, it can add to his feelings of depression. Also, the fear of his demonic powers getting out of control and harming those he loves is often explored, which can lead to his depressed state as he tries to keep his powers in check while also living a somewhat normal life.
One common theme is the clash of different power structures. In 'ao no exorcist', there are exorcist powers and demon - slaying swords, while in 'kuroshitsuji' there are demon contracts. When these two worlds cross, seeing how the characters with different power sources interact is a big theme.
One theme that pops up a lot is the struggle with their exorcist duties while also dealing with their feelings for each other. They have to fight demons and protect the world, but at the same time, they are developing these complex emotions. It's like a balance between their personal lives and their responsibilities. And also, the theme of acceptance is there. They have to accept each other's flaws and strengths as they get closer.
A lot of fanfics focus on the idea of Amaimon protecting Shiemi in some way. Given his power and her relative vulnerability in some aspects, this makes for an interesting plot. Also, there are fanfics that deal with the theme of self - discovery for both characters. As they interact more, they learn more about themselves, especially in relation to their feelings for each other. This can be really fascinating as it delves deeper into their personalities than the original work might have.
I'm not sure if there is a specific 'rin and shiemi pregnant fanfic' out there. There are countless fanfics on the internet, and it might be difficult to find one with this exact theme. You could try searching on popular fanfic websites like Archive of Our Own or FanFiction.net.