Plagg, Adrien's kwami, is also a common character. He might befriend the sister too. He could be the one to break the ice between the sister and Adrien when it comes to the superhero side of things. He might play pranks on the sister or give her some advice on how to handle Adrien's moody days.
Marinette is often a popular character. Since she has a relationship with Adrien in the original series, in the fanfiction, she could interact with the sister in various ways. Maybe they become friends, or there could be some initial jealousy from Marinette if she thinks the sister is getting too much of Adrien's attention.
One interesting plot could be the sister helping Adrien deal with his double life as a model and a superhero. For example, she might accidentally discover his secret identity and then work behind the scenes to keep it safe from Hawk Moth.
Well, in Adrien Agreste depressed fanfiction, it often delves deep into his complex character. His depression could be due to his strict family life, especially his over - controlling father. Fanfiction writers might explore how he copes with his dual identity as a model and a superhero. They may show his isolation and how he tries to hide his true feelings from his friends.
Nathalie might be a character in these fanfictions too. Given her role in Adrien's life in the original series, she could be involved in the events leading up to his akumatization. Maybe she accidentally triggers his negative emotions. And then there's Gabriel, Adrien's father. His actions or lack of actions towards Adrien could be a major factor in Adrien getting akumatized. So, he could be a key character in the fanfiction, either as someone who realizes his mistake and tries to help or as someone who makes the situation worse.
The theme of unrequited love can also be present. He might feel that Ladybug will never truly love him for who he is, especially when he is in a depressed state. This adds another layer of sadness to his character and the story.
The Hawk Moth or Shadow Moth can be a significant character in these fanfictions. His presence can create a sense of danger and urgency. In a time travel plot, he could be trying to use the time - traveling situation to his advantage, like finding a way to get the Miraculous in a different time period. This makes him a powerful antagonist in the Adrienette time travel fanfiction world.
In many fanfics, female Adrien is portrayed as having a strong sense of justice, just like the male version. However, she may show it in a more empathetic way. For instance, when dealing with akuma - victims, she might be more in tune with their emotions and try to help them on a deeper emotional level. Also, her relationships with other characters, especially with Chloe, can be more complex. Since they are both girls, there could be more of a cat - fight - like dynamic in some stories.
Sasuke could be involved. He might be initially suspicious of Naruto's new - found sister but later come to respect her skills. Kakashi could also play a role as a mentor figure to both Naruto and his sister, guiding them in their ninja training. Another character could be Hinata. She could befriend Naruto's sister and help her adjust to life in the village.
Adrien could meet other mysterious figures in the lair. It could be an old acquaintance of his father's who has been helping with his secret plans. Or perhaps he'll come across a captive who was being held by his father for some unknown reason.
One common plot twist could be that the kidnapper is actually someone close to Adrien, like a jealous acquaintance who wants to get back at him for some perceived slight. Another might be that Adrien has a secret power or connection that the kidnappers are trying to exploit. Maybe he has a hidden family heirloom that they think is valuable.
One plot idea could be that Lila tries to frame Adrien for something he didn't do, but Adrien manages to prove his innocence with the help of his friends. This would create a lot of drama and tension in the story.