Well, this kind of fanfiction could start with Marinette making a mistake while using the Miraculous. Then she finds herself in the form of a Kwami. She might be really tiny and have to find ways to get around. She could hitch rides on people's shoulders or use her small size to her advantage when it comes to spying on Hawk Moth. And she would definitely have to deal with the fact that she can't just transform back into her normal self right away, leading to all sorts of comical and tense situations.
One popular theme is the exploration of the Kwamis' personalities. For example, Tikki's positive and guiding nature can be delved into more deeply. Another theme is the relationship between the Kwamis and their holders. How they interact, communicate, and support each other during battles and in daily life. Also, some fanfictions focus on the origin of the Kwamis, creating backstories that are not fully explored in the original series. This could include where they came from before they were associated with the Miraculous jewels and how they came to be part of the whole Miraculous system.
One possibility could be that humans with Kwami would have extraordinary powers similar to the Miraculous holders. They might use these powers for both good and bad, creating a whole new dynamic in the Miraculous Ladybug universe. For example, a human with the Kwami of creativity could come up with amazing solutions to problems, but also be tempted to use it for personal gain at the expense of others.
The social structure in the Miraculous Ladybug world would also be altered. Humans with Kwami might form groups or factions. There could be those who believe Kwami should be used for the greater good only, and others who think they can use their powers freely. This would lead to conflicts and alliances, much like in real - world politics.
Definitely Ladybug and Chat Noir. They are the central characters, and a Kwami swap for them means a whole new set of challenges and adventures. For example, how they interact with each other when they have different powers and how they adapt to the changes. Also, Rena Rouge could be an interesting character to focus on in Kwami swap fanfiction. Maybe she gets involved in helping the heroes deal with the consequences of the swap, or perhaps her own Kwami gets swapped in some way, adding another layer of complexity to the story.
In a Kwami swap fanfiction, a possible plot is that the swapped powers start to have unforeseen side effects on the holders' daily lives. Ladybug, for instance, might find it difficult to balance her normal life with the new Kwami - influenced powers. Chat Noir could be in a similar situation. As they struggle to deal with these changes, they also have to figure out how to reverse the Kwami swap. Meanwhile, the city is in more danger than ever as they are not at their full potential, and this could lead to some intense and exciting battles and rescue scenes.
Tikki is really interesting. She's the Kwami of Creation and is always positive and full of wisdom. There are so many aspects to explore, like how she encourages Marinette in difficult situations. Plagg is also great. His mischievous nature as the Kwami of Destruction provides a lot of comical and interesting storylines. Another one is Wayzz. His calm and knowledgeable demeanor makes him a great character to write about, especially when it comes to guiding his holder about the powers and history of the Miraculous.
Well, a great plot twist could be in the relationship between Lady Noir and Chat Noir. Since the kwami swap, their dynamic might completely change. Maybe Lady Noir, with her new powers from the swap, becomes more dominant in their partnership, which could cause some tension or new levels of cooperation between them. Also, it could lead to different reactions from the villains who are used to their normal powers and interactions.
One interesting plot could be that Marinette - as - Kwami is accidentally discovered by Hawk Moth. He tries to capture her to use her powers for his evil plans. Marinette then has to use her wits and any new Kwami - like abilities she has to escape and warn Ladybug (who she can't transform into at the moment). This would create a lot of tension and action in the fanfiction. Also, it could explore how Marinette feels being in such a vulnerable state.
If the kwami swap involves a kwami with a mischievous nature, Lady Noir's personality could become more playful. She might start cracking more jokes during battles, much like Chat Noir usually does. This would change her overall demeanor and how she interacts with both the villains and Chat Noir. It could also make their partnership more light - hearted or, if Chat Noir isn't used to it, a bit more chaotic as they adjust to this new side of Lady Noir.