Perhaps the story could start with the unexpected news of Marinette being pregnant. Luka is overjoyed but also a bit nervous. As the baby arrives, they learn a lot about themselves and their relationship. The baby might have some unique characteristics that seem to be related to the magic in their world, like having an affinity for music that is so strong it seems almost miraculous, just like the powers they are used to dealing with.
One possible plot could be that Marinette and Luka are living a happy life with their baby. They might face some challenges in balancing their superhero/villain - fighting duties (if in the Miraculous Ladybug universe) and taking care of the baby. For example, they could be worried about protecting the baby from any potential threats related to their secret identities.
One possible plot could be that Luka has been mind - controlled by an akuma. In the Miraculous Ladybug universe, akumas often make people do things they wouldn't normally do. So, he kidnaps Marinette not out of his own will but because of the akuma's influence. Marinette might initially be shocked and scared, but then she could try to find a way to break the akuma's hold on Luka and save them both.
Their relationship would likely become more solid. Having a baby together means they are sharing a huge responsibility. They would have to depend on each other more, which would strengthen their bond.
It could also create some drama. Maybe Marinette still has feelings for Adrien, and the kiss with Luka makes her confused. This could lead to a complex love triangle - like situation where she has to figure out her true feelings.
There could be a lot of internal conflict. Marinette might be used to her shy yet determined self, and Adrien his more reserved but princely nature, and Luka his laid - back attitude. When merged, they'd have to reconcile these differences within the new entity. This could lead to a very character - driven story as they learn to function as one.
The theme of hidden identities also exists. Given the context of the Miraculous world they live in, sometimes their identities as heroes or normal teens are explored in relation to their relationship. It adds an extra layer of mystery and drama to the fanfiction, making it more engaging for the readers.
Marinette would likely be very frightened at first. She might scream or try to fight back. After all, being kidnapped is a terrifying situation.
There are also some Miraculous Ladybug - focused fan communities on social media platforms like Tumblr or Reddit. Fans often share links to their favorite fanfictions there. You might find some great stories about Marinette and Luka's kiss by simply asking in the relevant groups or by searching through the existing posts.
There's also 'The Luka - Marinette Connection'. In this fanfiction, the connection between Luka and Marinette is explored on a deeper level. It starts with Luka noticing Marinette's little quirks and how she tries to hide her feelings. As the story progresses, they start to open up to each other more. The author creates a really engaging story by adding in some mystery elements related to the Miraculous and how it might affect their relationship.
There are many interesting fanfictions about Marinette and Luka. Some might focus on their relationship development outside of the superhero chaos. For example, a fanfiction could explore how they go on a simple date, sharing their interests like Marinette's fashion design and Luka's music.
One possible aspect of this fanfiction could be exploring the relationships between Adrien, Marinette, and Luka. Maybe it's a story where their personalities merge in some magical or scientific way. For example, their combined traits could lead to a new superhero or a character with a very unique set of skills and emotions.