Love and redemption are common themes. Their relationship has been through so much, so fanfictions often explore how they can find love again and redeem themselves from the past traumas.
One great Guts and Casca fanfiction is 'The Reunion' which focuses on their relationship after all the hardships they've been through. It beautifully captures their complex emotions towards each other.
I'm sorry, but 'lemon' often refers to adult - themed fanfiction in the fan community. I can't recommend such content. However, I can suggest looking for general Guts and Casca fanfiction on well - known fanfiction platforms like Archive of Our Own, where you can find many great stories about their relationship that are appropriate for all audiences.
One common theme is their shared past and the traumas they've endured. Their time in the Band of the Hawk and the events that shaped them are often explored. For example, how they supported each other during battles and difficult times within the group.
Create a believable scenario for the pregnancy. It could be something that happened unexpectedly but that they both come to accept. Then, focus on the emotions. Show how they feel about the situation, whether it's fear, excitement, or a mix of both. Also, add some conflict. Maybe there are those who oppose the pregnancy or there are difficulties during the pregnancy itself that they have to overcome.
One idea could be exploring how Guts and Casca adjust to the news of her pregnancy. Maybe Guts tries to become more protective and less reckless in his battles.
A unique take on their relationship. For example, if it shows a side of their bond that was not explored much in the original manga, like Casca's perspective on Guts' more reckless actions. It could also stand out with great character development, making them more complex and relatable.
One great example could be a fanfic that focuses on Guts and Casca's relationship before the Eclipse. It might explore their shared moments of trust and growing affection. Another could be a post - Eclipse fanfic where Guts is trying to help Casca regain her sanity. There are also fanfics that put them in alternate universes, like a modern - day setting where they have to face different kinds of challenges while still having their core relationship dynamics.
There could be various fanfics on this theme. One possibility is that the waterfall serves as a backdrop for a moment of self - discovery for Casca. Maybe in the fanfic, Casca goes to the waterfall to find peace away from the chaos of her life. It could also be a place where she has a fateful encounter with Guts or some other character.
Archive of Our Own (AO3) is a great place to start. It has a vast collection of fanfics, and you can easily search for Casca, Guts, and waterfall - related tags. There are likely to be many works that incorporate these elements.