It could vary a great deal. Maybe it focuses on the relationship between the girl and Marth, perhaps exploring how she supports him from behind the scenes in his adventures.
The plot of 'the girl behind marth fanfic' may also include elements of mystery. Maybe the girl has a secret past or a special power that only she and a few others know about. This secret could be related to Marth in some way, like she has the key to helping him achieve a certain goal, or her past is somehow intertwined with his destiny. And as the story progresses, we see how this all unfolds and affects their relationship and the overall story.
Well, I haven't really read a particular 'the girl behind marth fanfic' myself. However, you can ask in fanfic communities or forums. People there are often really into fanfics and might be able to point you to some great ones with 'the girl behind marth' theme.
I can't really say for sure as it depends on the writer. But it might involve the character Agent 8 in some sort of adventure or relationship situation that is unique to the fanfic writer's imagination.
Since I haven't actually read a specific 'maou and chiho lemon fanfic', it's hard to say exactly. But generally, it might involve some romantic or tense interactions between Maou and Chiho with some added elements of drama or adventure.
I'm not very familiar with the specific 'yasuo karma lemon fanfic', but generally in fanfics that have a 'lemon' tag, there might be some romantic or more intimate interactions between Yasuo and Karma. It could involve their relationship developing in a more passionate way compared to the regular League of Legends lore.
Since I'm not very familiar with specific 'big mac and a changling fanfic', it's hard to say the exact plot. But generally, it could involve some kind of relationship development between Big Mac and the Changling.
Often, it might involve Natsu and Yukino going through some sort of emotional journey together. Maybe they start off as friends or acquaintances and gradually develop deeper feelings. Their relationship could be tested by various challenges in the story.
Often, it might involve the relationship between Percy Jackson and Khione. There could be elements of adventure intertwined with their growing relationship, perhaps with challenges they face together in the Percy Jackson - style mythological world.
One common theme is friendship. Given their roles in the Fire Emblem series, many fanfics explore how ike and marth become friends, support each other in battles and in their respective kingdoms' affairs.
One common theme is friendship. Their mutual respect and admiration for each other often lead to a strong friendship in fanfics. Another theme is loyalty, as they are both loyal to their respective kingdoms and this loyalty can be explored in relation to their relationship.
In 'roy x marth fanfic', a prevalent theme is the bond between them. This bond can be a brotherly one or something more profound. The theme of heroism is also common. They are both heroic figures, and fanfics might show them saving each other or their kingdoms. Additionally, the exploration of their different cultures and how they bridge the gap between them is another recurring theme.