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.
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 possible fanfiction could be about Marinette's daily life with Tikki. For example, Marinette could be having a tough day at school, getting bullied by Chloe. Tikki, being her kwami, tries to cheer her up by suggesting they make some special macarons. They then spend the evening in Marinette's room, sharing stories and laughing, which helps Marinette forget about her bad day.
One possible scenario in a fanfiction could be that Lila finally realizes the error of her ways and decides to make amends with Marinette. She might see how Marinette's kindness has always been genuine despite her lies, and they could gradually become friends. This would be a big character development for Lila.
A really interesting fanfiction idea could be that Lila and Marinette switch personalities for a day. This would be a comical yet thought - provoking situation. Lila would have to deal with Marinette's responsibilities and kindness, while Marinette might struggle with Lila's devious ways. It could lead to both of them having a new perspective on each other.
A simple reason for Marinette's depression could be the stress of her double life. Juggling school, friends, and being Ladybug is just too much for her, so she gets depressed.
One possible story could be that Marinette is depressed because she feels like she's constantly failing as Ladybug. Maybe she made a big mistake during a battle that led to some destruction in Paris. So, she starts to doubt herself and becomes withdrawn.
One idea could be that Hawk Moth is behind the kidnapping. He might have discovered Marinette's identity as Ladybug or suspect her. He could use her to try and get the Miraculous. Maybe he offers a trade to Chat Noir, the Ladybug Miraculous for Marinette's safe return.
There are many interesting aspects in fanfictions regarding Marinette's armor in Miraculous Ladybug. One possibility could be that the armor gives her enhanced powers, like being more resistant to akuma attacks. Maybe it has special designs that are related to her Ladybug identity, with red and black patterns that are more intricate than her normal suit.
One possibility could be that in the fanfiction, all of Marinette's friends plan a huge surprise party for her. They decorate her room with pink and white balloons, her favorite colors. Alya might be in charge of inviting everyone secretly, while Adrien brings a special, handmade gift that he's been working on for weeks, showing his deep affection for Marinette in a way that's still in - character for the show.