One possible scenario in a fanfiction where Lila is exposed could be that Marinette finally gathers enough evidence of all of Lila's lies. Maybe she records Lila admitting to her lies when she thinks no one is listening. Then Marinette presents this evidence to Adrien and their friends. They are initially shocked but then realize how they've been manipulated by Lila all this time.
Well, Lila could be exposed when she tries to claim credit for something that the Miraculous heroes did. For instance, she says she helped Ladybug defeat an akuma when in fact she did nothing. Then, Tikki, Marinette's kwami, could find a way to let everyone know the truth. Maybe she uses her magic in a subtle way to make Lila blurt out the truth.
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.
It could be the protagonist. The one who has always been suspicious of Lila's stories and has been quietly investigating. They might finally gather enough evidence and expose her.
One great Lila fanfiction could be one where she has a change of heart. Maybe she realizes the error of her ways after being exposed to real friendship. For example, in a story, Ladybug and Chat Noir could show her kindness despite her lies, which makes her question her actions and start to become a better person.
In many fanfictions about Lila and Adrien, their relationship can be quite complex. Sometimes, Lila tries to manipulate Adrien to get closer to his famous family or for her own gain. But Adrien, being the kind-hearted person he is, might initially be deceived by her lies, only to gradually realize her true nature as the story progresses.
Well, in such a fanfiction, perhaps Lila's lies are finally revealed to all the characters who have been deceived by her. For example, if it's set in a school - like Miraculous Ladybug setting where Lila has been lying about her achievements and connections, she might be exposed during a big event at school, like a speech or an award ceremony.
In some fanfictions, Lila's scheme against Adrien could be part of a larger plot. She could be working with an enemy of the Miraculous holders. Since Adrien is Chat Noir, she might try to expose his identity or put him in dangerous situations to further her own goals. For example, she could pretend to be in trouble to lure Chat Noir into a trap set by the villains she's allied with.
One popular type of fanfiction might be where Lila tries to manipulate Nathaniel for her own gains, but Nathaniel sees through her eventually. For example, in some fanfictions, Lila might try to use Nathaniel's artistic skills to create false evidence against Ladybug, but Nathaniel realizes that Ladybug is a hero and refuses to be part of Lila's schemes.