Often, there are side characters like the other demons in the realm. Some might be friends or foes to the big sister and the reader. For example, a mischievous imp - like demon who likes to play pranks on the reader but is ultimately harmless can be a popular side character.
A really engaging plot might be where the reader discovers that they have a special power that the big sister demon needs. But instead of using the reader, she decides to help the reader master this power. In the process, they face many challenges together like dealing with power - hungry demons who want to steal the reader's power. This journey of mutual growth and protection can be a great plot for this type of fanfiction.
One great story could be 'The Demon Sister's Protection'. In it, the demon sister uses her powers to keep the reader safe from various supernatural threats. It has a really engaging plot with a lot of action and some sweet moments between the two characters.
A common theme in 'overprotective big sister x reader fanfiction' is conflict. There can be external conflicts like other characters trying to harm the reader, which the sister has to fend off. But there are also internal conflicts, such as the sister's struggle between being overprotective and allowing the reader to have their own experiences. This creates a lot of drama and tension in the story. Additionally, the theme of unconditional love is prevalent. The sister loves the reader without any conditions, and this love drives her actions throughout the story, whether it's scolding the reader for being reckless or celebrating their achievements.
Finding good 'overprotective big sister x reader fanfiction' can take a bit of time. You could also ask in relevant fan communities on social media platforms. For example, on Tumblr, there are often groups dedicated to different types of fanfiction. They might be able to point you to some hidden gems. The best part about this type of fanfiction is that it often explores the relationship dynamics between the two characters in a very emotional and sometimes comical way.
First, establish the relationship between the sister and the male reader. Show their shared history, like how she's been overprotective since he was a kid. Then, introduce a conflict. Maybe the male reader wants to go on a trip alone, but the sister is against it. Build tension as they argue about it. As the story progresses, let the male reader start to break free a bit, which makes the sister realize she needs to let go. This creates an interesting character arc for both of them.
A frequent trope is the overprotective big sister being extremely possessive. She sees the male reader as her 'little boy' even when he's grown. In some fanfictions, this can lead to conflicts within the family. Also, she may be the first to jump to his defense in any situation, whether it's a minor argument with a neighbor or a more serious issue at school or work. She's like his personal bodyguard in a sense.
You should also plan out the relationship arc. Will it be a slow - burn romance or a more instant connection based on mutual understanding? For example, you could have the reader initially be afraid of the demon sister but then gradually see her good side. Also, don't forget to add some conflict, such as other supernatural beings who oppose their relationship or the demon sister's own internal struggles.
The theme of redemption can also be found. Sometimes the demon in the fanfiction is on a path to redemption because of the influence of the reader. It gives the story a deeper meaning. Also, there's the theme of mystery. Demons are mysterious by nature, and the fanfiction often plays on that, with the reader trying to figure out the demon's true motives and nature as the story progresses. This keeps the readers hooked.
For the male demon reader's character, you can start with his appearance. Maybe he has red eyes and black horns. His personality could be a bit of a rebel in the demon world. He's not fully evil but has a sense of mischief. He should also have some unique powers like the ability to control shadows, which would make him an interesting character when interacting with Elsa.