Well, in 'ghirahim x reader fanfiction', one frequent theme is the struggle between good and evil. Ghirahim is often seen as an ambiguous character in terms of morality. So, the fics may explore how the reader influences his actions towards either side. Also, there's the theme of loyalty. Whether Ghirahim can be loyal to the reader or vice versa is often a topic. There are also themes related to self - discovery for the reader as they interact with such a complex character like Ghirahim. They might learn more about themselves in the process of dealing with him.
A common theme is the power dynamic. Since Ghirahim is a powerful character, often there's exploration of how that power affects his relationship with the reader. Another theme is the discovery of the unknown. The reader usually enters Ghirahim's world which is full of mystery.
One common theme might be the redemption of Ghirahim. Writers may explore how he could turn from his villainous ways. Another could be his relationship with other characters in a more positive light, like developing an unexpected friendship or alliance.
A common theme is the exploration of their opposing natures. Ghirahim is often depicted as a villain or at least an antagonist, while Link is the hero. Their relationship in the fanfiction usually involves a struggle between good and evil. Another theme is the idea of redemption. Sometimes Ghirahim is shown as having the potential to change because of Link.
Another theme could be the idea of forbidden love. Given their different allegiances in the Zelda universe, a relationship between them would be considered against the norm. Writers often play with this concept, creating stories full of tension and drama.
I'm not very familiar with this specific type of fanfiction, but generally, themes could include the relationship between Ghirahim and Link evolving in a unique way due to the pregnancy. There might be themes of protection, as Link would be in a vulnerable state. Another could be the reaction of the characters in the Zelda universe to this unexpected situation.
The theme of transformation is also present. As their relationship develops, both characters might change in some ways. For example, Fi might become more open - hearted due to Ghirahim's influence, and Ghirahim might become more reflective. These changes are often central to the plot in many 'ghirahim x fi fanfic'.
Common themes in this type of fanfiction include the exploration of good and evil. Ghirahim is clearly on the side of evil, while Link is the epitome of good. Fanfic writers like to play with how these two forces interact. The theme of obsession also appears. Ghirahim's fixation on Link can be a central theme, whether it's his desire to defeat Link or something more complex. And then there's the theme of growth. Through their interactions, both characters may experience personal growth, with Link becoming more confident in his abilities and Ghirahim perhaps evolving in his understanding of the world and his place in it.
One popular 'ghirahim x reader fanfiction' is 'A Meeting with Ghirahim' which has an interesting plot where the reader accidentally stumbles into Ghirahim's realm. Another great one could be 'Ghirahim's Unexpected Bond' that focuses on the development of an unusual relationship between Ghirahim and the reader. You can find these on major fanfiction platforms like Archive of Our Own.
Rather than seeking lemon fanfiction, you could explore general 'ghirahim x reader' fanfiction that focuses on the relationship in a more appropriate and positive way.
A sense of belonging is another big theme. The reader, who may feel like an outsider in the real world, finds a place where they belong among the mutants. There are also themes related to fighting for justice, just like the X - Men do in the original stories.
One common theme is adventure. Since Chekov is part of the Star Trek universe, many fanfictions involve the reader going on adventures with him through space, exploring new planets and facing various challenges.