A lot of these fanfics have the theme of cooperation. Since they are often in some sort of situation together, they have to work together. This cooperation can lead to a deeper connection between them. There are also some fanfics that explore the theme of forgiveness. If they have had some sort of misunderstanding in the past, they learn to forgive each other and move forward in their relationship.
A prevalent theme is adventure. The stories usually involve Kasumi and the OC going on various quests or facing dangerous opponents. This gives the opportunity for exciting fight scenes and exploration of different areas in the DOA universe. Also, the theme of loyalty often comes up. The OC may prove their loyalty to Kasumi or vice versa during difficult situations.
One great Doa Misaki x Kasumi fanfic is 'The Bond Between Them'. It beautifully explores their relationship through various adventures. The author does an amazing job of bringing out their personalities and how they interact with each other.
One common theme is friendship. Usami and Misaki's friendship is often explored deeply in fanfics. Another theme is growth, like how they both grow as individuals within their relationship. Romance is also a big theme, with many fanfics delving into their romantic feelings for each other.
In saruhiko x misaki fanfic, self - discovery is a recurring theme. As they get closer, they also discover more about themselves. And the theme of acceptance is also there. They have to accept their feelings for each other and also accept each other's flaws as their relationship progresses.
One common theme is friendship evolving into something more. Misaki and Fushimi start with a certain relationship, and in fanfics, it often develops deeper feelings. Another theme could be redemption. Maybe Fushimi has made some mistakes in the past, and Misaki helps him redeem himself through their relationship.
Friendship is a very common theme. They are often portrayed as starting from being strangers or having some initial misunderstandings and then growing into good friends.
One great kasumi doa and oc fanfic is 'Kasumi's New Adventure'. It has an interesting plot where the OC (original character) teams up with Kasumi to face various challenges in the DOA universe. The story is full of action and also delves into the relationship between the two characters.
Well, in these fanfics, a frequent theme is the exploration of unspoken feelings. Drunk Misaki may act in ways that he wouldn't when sober, and this can be a catalyst for the relationship to progress. For example, his inhibitions are lowered, so he might be more affectionate towards Usagi. There's also the theme of trust, as Misaki has to trust Usagi in his drunken state, and Usagi has to respect Misaki's vulnerability.
I can't really speak to the common themes in 'usui x misaki lemon fanfic' specifically as I don't have a collection of such fanfics to analyze. But generally in fanfics about a romantic pairing, themes could include love, relationship development, and overcoming obstacles. However, since 'lemon' often implies mature content, it might also involve more adult - themed relationship aspects which I can't elaborate on further due to inappropriate nature.
One common theme could be the development of their relationship. It might show how they grow closer and understand each other better. Another theme could be the exploration of their personalities within the context of their relationship. For example, how Usagi's confident nature and Misaki's more reserved side interact.