Sometimes, Tumblr can also be a good source. There are many bloggers on Tumblr who are into anime fanfiction. However, the search function might be a bit tricky, so you may need to use specific tags related to the show, the characters Sadao and Emi, and fanfiction.
The theme of power dynamics between them is also quite popular. Given that Sadao is a demon and Emi is an angel, their different powers and how they interact with each other in various situations, such as in battles or when they are forced to cooperate, are often explored in fanfiction.
A common theme is the relationship between Emi and Maou. Whether it's a slow - burn romance or a more platonic friendship evolving, it's often explored.
Another way is by exploring their pasts. Maybe they discover that they have more in common than they thought in terms of their upbringing in their respective worlds. This newfound knowledge can make them more empathetic towards each other. For instance, if they find out that they both had a mentor figure who had a big impact on their lives, it could create a bond.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions from various fandoms, including Devil Part Timer. The tagging system there helps you to easily find the stories you might be interested in.
A prevalent theme is adaptation. The devil has to adapt to the human world in order to survive, and Emi also has to adapt to co - existing with him. Also, the theme of redemption can be seen sometimes. Maybe the devil starts to do good things in the human world, which is a form of redemption for his past actions in their demon world.
The appeal often lies in the relationship between Maou and Emi. Their dynamic, being from opposite sides originally, is very interesting.
One great fanfiction could be 'The Unlikely Alliance' where Emi and Maou have to team up in a different way than in the original story to face a new threat. It has really interesting character development.
One popular fanfiction might be 'Maou and Emi's New Adventure' where they face a new threat in the human world together. It's full of their typical banter and some sweet moments.
Well, a plot could involve the devil getting into some modern - day human trouble, like accidentally getting involved in a corporate scandal. Emi then has to bail him out while also dealing with her own demon - related issues. It could also be about Emi trying to teach the devil some modern human values, which he constantly resists in a humorous way.
Their relationship can be developed through shared experiences. For example, if they go on a mission together to save a human from a demon's curse. During this mission, they would have to rely on each other, communicate more, and understand each other's strengths and weaknesses better. This would bring them closer and deepen their relationship.