One popular 'yandere Sadao Maou x reader fanfic' might be found on fanfiction.net. You can search there using the relevant tags. However, the availability and popularity can vary.
Well, in 'evil Sadao Maou x reader fanfic', a frequent theme is the struggle between good and evil within the relationship. The reader may be a force for good trying to change Maou's evil ways. Also, themes of loyalty and betrayal can be present. Maou's actions as an 'evil' character might lead to situations where the reader has to decide whether to stay loyal or turn away. And sometimes, there's the theme of forbidden love, as being associated with an 'evil' character like Maou can be seen as something taboo in the story's context.
I'm sorry I can't directly recommend specific 'evil Sadao Maou x reader fanfic' as it depends on various fanfiction platforms. You could try searching on popular platforms like Archive of Our Own (AO3). There might be a lot of works there that fit this category.
First, create conflict. For example, Maou's dark nature could lead to situations where he accidentally endangers the reader. This builds tension. Then, develop their relationship gradually. Don't rush into love. Let them learn about each other's quirks and secrets over time. Also, introduce side characters that either support or oppose their relationship. This adds more complexity. For instance, other dark beings who don't like Maou getting close to a human reader.
Common themes often include trust. Given Maou's dark side, it takes time for the reader to trust him and vice versa. There's also the theme of discovery. The reader gets to discover the different layers of Maou's personality. For example, beneath his dark exterior, there could be a more vulnerable side. And the theme of sacrifice might be present. Maou might have to sacrifice some of his dark desires or power for the sake of the relationship with the reader, or the reader might sacrifice something for Maou.
The theme of redemption also pops up often. Sadao Maou may be seen as a 'bad' character initially, but through his relationship with the OC, he may start to show signs of redemption. The OC might inspire him to make different choices, and this exploration of his character's potential for good is a recurring element in these fanfics.
One common theme is the intense and often obsessive love of the yandere character, Sadou Maou. For example, he might go to extreme lengths to protect the reader. Another theme could be the power dynamics, as Sadou Maou might have some sort of power that influences the relationship with the reader. Also, the internal conflict of the reader in dealing with such an overbearing and obsessive love can be a theme. They might struggle between being drawn to Sadou Maou's passion and being frightened by his extreme behavior.
Well, writing a good 'yandere sadou maou x reader fanfic' is not easy. You should start by creating a strong plot. Maybe start with an event that brings the reader and Sadou Maou together, like a shared class project or a chance encounter in a strange place. Then, when it comes to Sadou Maou, show his yandere traits subtly at first. For instance, he might give the reader a little too much attention or be a bit too possessive over small things. For the reader, make them relatable. They could be an ordinary person thrown into this extraordinary situation. And finally, keep the pacing right. Don't make the story drag, but also don't rush through the important parts, especially the development of the relationship between the two characters.
Well, 'OC's Impact on Maou's Realm' is another one. In this fanfic, the OC has unique abilities that disrupt and also improve Maou's world. It's an exciting read as it shows how the OC's presence affects the existing characters and the overall story arc in the world of Sadao Maou.