One possible storyline could be that Ladybug sacrifices herself to save Paris from an ultimate villain. Maybe the villain has created a weapon that can destroy the entire city, and Ladybug uses her powers to contain the blast at the cost of her own life. Her death would then lead to a city in mourning and Chat Noir having to step up in a whole new way, trying to keep Paris safe without his partner while also dealing with his grief.
In a different take, Ladybug could be poisoned by an enemy who discovers her civilian identity. As she slowly succumbs to the poison, she tries to pass on her Miraculous to someone she trusts in secrecy. This would create a power struggle as different characters vie for the role of the new Ladybug. Meanwhile, Chat Noir is left in the dark about what's happening until it's too late, and he has to face a Paris without Ladybug and a new, perhaps unready, hero in her place.
One possible storyline could be that Ladybug and Cat Noir have to protect a powerful Tibetan artifact from Hawk Moth. The artifact might have some sort of special power that Hawk Moth wants to use for evil. Another idea is that they encounter new kwamis in Tibet that are unique to the region and have to learn how to work with them. Maybe there are also local heroes in Tibet who team up with Ladybug and Cat Noir to fight against the villains.
One possible storyline could be that Ivan writes a song for Mylene. He pours his heart into the lyrics, expressing his deep love for her. Mylene, in turn, is touched and decides to perform a dance to go along with the song for a school talent show. Their performance not only showcases their love but also brings the whole school together in a celebration of art and love.
In an akumatized Ladybug fanfiction, the akuma might enhance her powers in unexpected ways. For example, her Lucky Charm could become a more powerful and unpredictable object. Her akumatized form might also have a darker and more menacing look, perhaps with a more aggressive fighting style. Writers could explore how the heroes and villains interact with this changed Ladybug.
In a fanfiction, Ladybug could get hurt as a result of a trap set by Hawkmoth. He might have studied her fighting patterns and set up a situation where she is lured into a place full of obstacles that cause her physical harm. This would not only test her physical strength but also her mental resilience as she tries to figure out how to escape and continue her fight against evil.
A new villain could have a weapon that specifically targets Ladybug's powers. When she tries to use her yo - yo or her powers of creation, it backfires and causes her harm. This would force her to rely on her wits and Chat Noir more than ever. They would need to find a way to neutralize the weapon and heal Ladybug.
In this 'Miraculous Ladybug Criminal Ladybug Fanfiction', there could be a lot of potential storylines. One possibility is that an external force is influencing Ladybug to commit crimes. It could be a new villain who has found a way to manipulate the Miraculous. This would create a great conflict as Ladybug has always been the symbol of good. Her friends and allies would be in shock and would have to find a way to stop her without hurting her. The story could also explore her internal struggle, as she might be aware of what she's doing but unable to stop herself.
I can't really recommend or go into detail about spanking - related plotlines as they may not be suitable or appropriate for all audiences. However, in general Miraculous Ladybug fanfiction might explore different relationships between the characters, like Ladybug and Cat Noir's partnership, or their individual struggles with their secret identities.
One popular storyline could be Marinette having a dream about her future with Adrien while in her bed. In the fanfiction, she might see them getting married and living happily ever after. Another could be Chat Noir secretly visiting Ladybug while she's resting in bed and leaving her a small gift as a token of his affection without her knowing it was him right away.
In some fanfictions, there are storylines where new Miraculous holders from different parts of the world join the fight. These new characters bring in unique powers and cultures, adding more depth to the Miraculous universe. For example, a holder from an Asian country with a Miraculous related to an ancient mythical creature.
One interesting storyline could be an alternate universe where Marinette and Adrien have different Miraculous powers. For example, Marinette might get the Cat Miraculous and Adrien the Ladybug Miraculous. This would completely change their dynamic and how they fight against Hawkmoth.