Maybe it's a jealous acquaintance. If Kagami is really good at something, like she's a star in a particular activity, someone who is jealous of her success might set up a situation where she gets hurt. For instance, they could tamper with her equipment in a way that causes her to have an accident.
She might have a dark, twisted version of her usual pink and black color scheme. Maybe her pigtails would be wild and spiky, like they're full of dark energy. Her dress could be torn and tattered, with a more menacing style, and her eyes might glow a deep red color.
One possible story could be that Adrien gets akumatized because he feels constantly overshadowed by Ladybug. In this fanfiction, Hawkmoth might prey on his insecurities. As an akumatized form, Adrien could have enhanced physical abilities like super strength and speed. His akumatized look might be a dark version of his Chat Noir costume, with a more menacing appearance.
Hawkmoth is usually the main antagonist. Since he is the one who akumatizes Marinette in the first place. He takes advantage of her negative emotions, like her insecurities or anger, to turn her into an akuma and use her for his own evil plans.
Well, if Plagg gets akumatized in fanfiction, it could lead to some really chaotic situations. Plagg's powers are already quite strong as a kwami, and with the akuma's influence, they might become uncontrollable. For example, his cataclysm power could be misused on a large scale, causing destruction all over Paris. Maybe he would turn against Adrien and the other heroes, creating a big rift in their relationships and making it extremely difficult for them to fight back.
One interesting aspect could be the character transformation. Seeing Marinette, who is usually kind - hearted, turn into an akumatized form offers a fresh take on her personality. It can explore darker emotions and motives that she doesn't typically display.
Well, a fanfiction about Luka getting akumatized might start with a misunderstanding. Maybe he sees Marinette and Adrien together and misinterprets their relationship. As an akumatized character, he could have a really cool and menacing design. His akuma form might be named something like 'Melodic Mayhem' and his powers could involve disrupting the harmony around him, not just in a musical sense but also in people's relationships. This would force Ladybug and Chat Noir to think differently when fighting him.
One interesting Naruto akumatized fanfiction could be where Naruto is akumatized due to the constant ostracism he faces in the village. He becomes a powerful and dark force, with his chakra taking on a menacing aura. His appearance might change to something more foreboding, and his abilities could be enhanced in a twisted way, like his Rasengan becoming a destructive black hole - like attack.
Growth is also a big theme. Fans like to write about how Kuroko and Kagami grow as players and as people. They start from a certain point and through various experiences, they become better versions of themselves. It could be in terms of their basketball techniques or their ability to handle different situations.
One possible plot could be Marinette getting akumatized because she feels constantly overshadowed by Ladybug's responsibilities. She might turn into an akuma with powers that are a twisted version of her creativity, like creating chaotic and unmanageable 'designs' that cause havoc in Paris.