Ciel would likely become more protective. He has always been in a dangerous world, and now with a baby on the way, he'll do whatever it takes to safeguard his family. Lizzy, she might become more nurturing. She was already a strong character, but motherhood could bring out a softer, more patient side of her.
The plot also matters. A fanfic could be about their relationship evolving during a dangerous mystery they have to solve together. This gives the story an exciting backdrop and allows for interesting interactions between the two characters. It should have a good balance between their personal relationship growth and the external events happening around them.
Another reason could be that fanfiction gives them a sense of community. By loving and reading fanfiction, they can connect with other fans who have similar interests. They can discuss their favorite stories, share their thoughts on different interpretations of their characters, and feel part of a bigger group.
One of my favorite scenes in Ciel x Lizzy fanfiction is when Lizzy stands up for Ciel in front of others. It shows her loyalty and her growth from a somewhat sheltered girl to someone who can be a protector. Another great scene is when Ciel lets his guard down a little around Lizzy, like sharing a quiet moment in the garden. It's a rare moment of vulnerability for him.
In some ciel x lizzy fanfictions, there is a theme of self - discovery. As they interact more, they learn more about themselves. Ciel might discover a softer side of himself because of Lizzy, and Lizzy might find more strength in herself. Also, the theme of loyalty often comes up, as they prove their loyalty to each other in different situations in the stories.
There's also 'Ciel and Lizzy: A New Chapter'. This fanfiction takes a different approach. It starts with Ciel and Lizzy getting into an argument over a decision Ciel has made. But through the course of the story, they come to understand each other better. The writing style is engaging and it keeps you hooked from start to finish.
There may also be fanfictions that put them in modern settings. Like they are students in a high - school and have to deal with normal teenage problems while also nurturing their relationship. It could be really interesting to see how their characters adapt to the modern world.
Love and loyalty are common themes. Often, these fanfics explore how Lizzy's love for Ciel endures despite his dark secrets. Another theme is growth. Ciel may grow as a person because of Lizzy's influence, and vice versa.
In Kuroshitsuji fanfiction, Ciel and Lizzy often have a complex relationship. Lizzy is initially presented as a somewhat naive girl, but she has a deep affection for Ciel. Their relationship can be seen as a blend of childhood friendship and something more. Ciel, on the other hand, is burdened with his revenge and his role as the Earl. Sometimes, in fanfiction, their relationship is explored in different ways, such as Lizzy becoming more aware of Ciel's true self and trying to support him despite his dark secrets.
A fanfic could show a moment where Ciel is at his most vulnerable, and Lizzy is the only one there to comfort him. Perhaps after a particularly difficult encounter with a foe, Lizzy finds Ciel in his study, and she simply holds him without saying a word, which means a great deal to Ciel.