A possible plot could involve the Dragon Kwami falling ill. In the Miraculous world, this is a big problem as the Kwamis are essential. Ladybug and Chat Noir team up with other Miraculous holders. They have to search for a special cure that exists in an ancient, hidden place. Along the way, they face many challenges and learn more about the Dragon Kwami's origin.
In a fanfiction, the Dragon Kwami could be a bit of an enigma. It might have some secrets that not even the other Kwamis are fully aware of. It could be silent most of the time, observing everything around it. But when it does speak, it says things that are very profound and thought - provoking. This kind of characterization would make the Dragon Kwami more mysterious and interesting in 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.
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.
Let's make a Kwami named Luma. Luma could be a Kwami related to stardust. Its Miraculous could be a star - shaped hairpin. The superhero with this Miraculous would be able to fly faster than normal superheroes, and also have the ability to create a shield made of stardust that can protect from most attacks.
Maybe the Wolf Kwami has a special power that is different from the other Kwamis. A new villain wants to steal this power for their own evil plans. The story could focus on Ladybug and Chat Noir protecting the Wolf Kwami and its power. This would involve a lot of action and adventure scenes.
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.
One interesting idea could be the different powers and personalities that come to the fore when the kwamis switch. For example, if Tikki and Plagg switched, Ladybug might become more mischievous and Cat Noir more rule - abiding in a very different way. It could also lead to new dynamics in the battles against villains as the heroes have to adapt to their new powers and instincts.
Another way is to have the Kwami OC interact with the existing Kwamis in the Miraculous Ladybug universe. If your Kwami OC is Ember, which has the power of fire, it could meet Tikki and Plagg. They could have a conversation about how their powers are different yet related. This kind of interaction can add depth to your fanfiction.
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.
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.