One common theme is self - discovery. Since Zenitsu has a complex personality, many fanfics focus on him finding out more about himself, his powers, and his place in the world. Another theme is friendship. He often forms strong bonds with other characters in fanfics, like Tanjiro and Inosuke.
One common theme is protection. Since Nezuko is a demon and Zenitsu is a demon slayer, there are often stories about Zenitsu vowing to protect Nezuko from other demon slayers or more dangerous demons. Another theme is friendship. They develop a unique bond in the original story, and fanfics often explore that further, like how they support each other through tough times. And of course, there can be a bit of a romantic undertone in some fanfics as well.
Typically, tanjirou x zenitsu fanfic often focuses on their strong friendship. It might show how Tanjirou's calmness balances Zenitsu's more excitable nature. Also, their shared experiences in the demon - slaying world are a big part of these fics. For example, they might face a powerful demon together and their bond is strengthened through the ordeal.
One common theme is friendship. Female characters often form deep friendships with Zenitsu, helping him grow and overcome his insecurities. Another theme is adventure. They go on demon - hunting adventures together. For example, in many fanfics, they explore new regions in search of powerful demons.
A simple Nezuko and Zenitsu fanfiction could be that they go on a journey together. Along the way, they encounter other demon slayers who are initially skeptical of Nezuko. But Zenitsu stands up for her, explaining that she's different. This shows the depth of their friendship and how Zenitsu has come to trust Nezuko completely.