In this fanfiction, it could be that a powerful force in the underworld wants to see what would happen if a human and a demon had a child. So, it manipulates events to make Ciel pregnant. Ciel and Sebastian would initially be shocked but then gradually accept the situation. The story could detail how Sebastian protects Ciel during the pregnancy, how they prepare for the baby's arrival, and how they raise the child in a world that is not so accepting of their unique family situation. It could also show the growth of their relationship as they face this new chapter in their lives together.
One common theme is protection. Since Ciel is a baby in these fictions, Sebastian often takes on the role of a very protective figure, shielding Ciel from various threats.
Ciel would likely become more nurturing. He's used to being in a position of power and having to be tough, but with a baby, he'd soften up. Sebastian would have to suppress his more demonic tendencies. He couldn't be as cold - hearted as he usually is. His focus would shift from just serving Ciel to also protecting the new life.
One possibility is that Sebastian, being a demon bound to Ciel, initially resists this order out of his demonic nature. But as the story progresses, he starts to develop a strange form of 'love' that is a mix of his loyalty and a newfound emotional connection. Maybe Ciel makes this order as a way to gain more control over Sebastian in their complex relationship.
Well, it could be that Ciel gets a concussion while trying to solve a mystery in the underworld. Sebastian finds him unconscious and takes him home. As Ciel wakes up with a concussion, his vision is blurry and he has trouble recognizing Sebastian at first. This causes Sebastian to feel a strange sense of unease. He then devotes all his time to helping Ciel recover, and during this time, Ciel starts to rely on Sebastian more than ever, which changes the power balance between them a bit.
In a 'ciel and lizzy having a baby fanfiction', perhaps the story could focus on how they first find out about the pregnancy. It could be a moment of shock and then joy. They start making plans for the baby's future right away. Ciel might start thinking about how to protect his family better, and Lizzy could be thinking about the kind of upbringing she wants for the child. Their relationship could also deepen as they go through this new phase in their lives.
Well, in non - lemon fanfic, Sebastian is often depicted as a sophisticated, powerful demon who is bound by contract to serve Ciel. Ciel is a young, determined noble with a dark past. But in lemon fanfic which is inappropriate, it may distort their characters in improper ways for the sake of adult - themed content. So it's better to focus on their proper character traits from the original source like Sebastian's loyalty (in a non - inappropriate sense) to the contract and Ciel's intelligence and drive to seek revenge.
One plot idea could be that Sebastian discovers Ciel's praise kink during their daily interactions. Maybe Ciel blushes or shows a different reaction when Sebastian accidentally gives him a compliment. This could then lead to Sebastian using praise as a way to manipulate Ciel or to strengthen their bond in a more complex way.
A pregnancy plot in a Sebastian - Ciel Paris fanfic would be a very unique take. It would likely involve a significant departure from the original story's themes. Maybe the Paris setting could add some elements of mystery and romance. For example, they could encounter a powerful witch in Paris who casts a spell on Ciel that has unforeseen consequences related to pregnancy. Or perhaps in this fanfic, Sebastian and Ciel have a different kind of relationship that develops over time in Paris, leading to a situation where a pregnancy could be a part of the story. But it would definitely be a controversial and unexpected plot development.
There's also 'Baby Ciel's Adventures with Sebastian'. In this fanfiction, it shows cute and innocent interactions between baby Ciel and Sebastian as they navigate the manor and deal with the other servants in a rather comical way. It's a light - hearted read that many fans enjoy.
Well, perhaps there's a plotline where Sebastian treats Ciel like a baby in public situations. This could lead to some embarrassing moments for Ciel, but also show the unique bond between them. It might also involve Sebastian making decisions for Ciel without his consent, which then causes some conflict between them until they resolve it through better communication.