Another plotline could involve Cat Noir getting akumatized after a major defeat. He blames himself for not being strong enough and this self - loathing is exploited by Hawkmoth. His akumatized form might be focused on proving his worth by overpowering villains in a more violent and less heroic way. Ladybug would then have to not only stop the akumatized Cat Noir but also help him regain his confidence and sense of self.
Ladybug would be extremely shocked and heartbroken. She has always seen Cat Noir as her partner and friend, and to see him akumatized would be like losing a part of herself. She would be determined to save him at all costs, trying to find a way to communicate with him beneath the akuma's influence.
One possible fanfiction could involve Chat Noir being akumatized after a major argument with Ladybug. Maybe he feels constantly overshadowed or unappreciated. The akuma could enhance his negative feelings, making him more aggressive and less in control. His powers might become distorted, and he could start causing chaos in Paris. Ladybug would then have to find a way to reach out to the real Chat Noir inside the akumatized form and purify the akuma.
Hawkmoth, of course. He's always looking for opportunities to akumatize people, and Ladybug would be a huge prize for him. If he could find the right moment when Ladybug is feeling vulnerable, like after a big defeat or a personal crisis, he could send an akuma her way.
One consequence could be that he loses his standing as a hero in Paris. People who once looked up to him would see him as a traitor.
One possible plotline could be Cat Noir finally confessing his true feelings to Ladybug while having her Miraculous. He might struggle with the newfound power and the responsibility that comes with it. Another could be them teaming up in a more equal way than in the original, sharing their secrets and working together to face a greater threat.
One common theme is the struggle between Chat Noir's normal self and the akumatized version. There's often a battle within him as he tries to fight the akuma's influence. Another theme is the reaction of Ladybug and other characters. They are usually shocked and have to figure out how to save their friend.
Perhaps a plotline where the pregnant cat gets lost and has to fend for itself while being pregnant. It could face various challenges like finding food and a safe place to stay. Then, there could be a heroic rescue by either its owner or some kind animals. Also, there could be a plotline about the cat's pregnancy affecting its behavior. It might become more moody or affectionate, and the fanfiction could explore how those around the cat deal with these changes.
One possible plotline is that Ichigo discovers Nejibana in a hidden location. Maybe it's in an ancient temple in the Soul Society that has been long forgotten. He senses its power and decides to take it, not fully aware of what it can do. Then he has to figure out how to use it while being chased by those who don't want him to have such a powerful weapon.
In a fanfiction, Alix might get the Bunny Miraculous in a rather unexpected way. For instance, the Miraculous could be sent to her from an alternate future where she is the only hope. Once she has it, she struggles at first to understand the time - jumping abilities. But as she practices, she becomes a crucial asset in the fight against Hawk Moth. She could use the power to go back and prevent some of Hawk Moth's early akumatizations, changing the course of the battle.
Another plot could involve Chat Noir being akumatized by an akuma that was specifically designed to target him. Hawkmoth could have studied Chat Noir's behavior and weaknesses. Once akumatized, Chat Noir could start to turn Paris against Ladybug. He could spread false rumors or use his charm in a negative way. Ladybug would then need to prove her innocence and save Chat Noir from the akuma's control. This would require her to dig deep into their relationship and find a way to reach the real Chat Noir.