One idea could be that the Reverser's powers are amplified and he starts reversing not just individual actions but entire relationships in Paris. So, Marinette and Adrien's unspoken bond is reversed, making them avoid each other at all costs. Another could be that the Reverser targets Ladybug's and Chat Noir's memories of their superhero identities, causing chaos as they try to figure out who they are again while still having to fight akumas. A third idea is that the Reverser somehow manages to reverse the concept of good and evil in Paris, making the akumas seem like the heroes and the heroes like the villains, and Ladybug and Chat Noir have to find a way to reverse it back.
One interesting new character could be a young girl who has the power to sense when the Reverser is about to use his powers. She could be an ally to Ladybug and Chat Noir, helping them anticipate his attacks. Another could be a mysterious magician who was once affected by the Reverser's powers and now has a vendetta against him. He might have some unique magic that can counter the Reverser's reversals in certain situations. A third new character could be a tech - genius kid who creates gadgets that can detect and temporarily block the Reverser's power waves.
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 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.
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 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.
There are indeed. Fanfiction writers often come up with creative stories involving the wolf miraculous in the Miraculous Ladybug world. They might explore how a new holder of the wolf miraculous interacts with Ladybug and Chat Noir. It could be about a character who discovers the power of the wolf miraculous and has to learn how to use it to fight against Hawk Moth's akumas. You can also check fanfiction.net for some interesting reads.
This event in the fanfic could also lead to new characters emerging. Maybe someone would try to take on Ladybug's mantle in a different way. Or new villains could rise, seeing the opportunity in the chaos. The magic of the Miraculous might be affected too. Since Ladybug was an important part of the magical balance, her death could have unforeseen consequences on the powers and the Miraculous themselves.