Sabrina. Yes, she's allied with Chloé and occasionally is as much of a jerk as she is, but she also has no idea what real friendship is, and gets easily crushed. Her father gets fired in one episode and turned into an akuma, forgetting who she is, and she can't understand that Marinette needing to handle a personal thing the day before a project is due is not the same as Chloé refusing to do schoolwork. Heck, when she gets akumatized the first time, she's just invisible, and her outline shows that her outfit hasn't changed. What's more, season 4 reveals that Chloé locks her in a closet and makes her do her homework.
Chloé of all people became one in "Despair Bear": in the past, it's revealed that her mother walked out on her when she was just a child (complete with a picture of her crying her eyes out when it happens), stunting her emotional growth and leaving her clingy to Adrien because he was there to comfort her. In the present, Adrien threatens to break up his friendship with her, and the prospect of this turns her into a miserable, anxious wreck, showing just how damaged her psyche is. When her mother does show up she constantly insults and belittles Chloé, which leads her to exposing her miraculous and trying to create a disaster so she can look like a hero to impress her mother. She even asks her mother why she doesn't love her. In seasons 4 and 5 her jerkassery is cranked up, which causes her father and best friend to eventually turn against her and at the end of "Revolution" she is forced to live with her abusive mother. The episode ends with a lonely and broken teenager who has lost everyone and everything she's ever cared about somberly sobbing.
André Bourgeois is a Sleazy Politician who abuses his powers, but he is constantly bullied by both his daughter and absolute bitch of a wife. It's also revealed in "Sole Crusher" that his wife cheated on him some 15 years ago, and that he had to give up his aspirations to become a film director to get in good graces with his wife, burying his dreams.
Kagami. Her mother, Tomoe is even more suffocating than Adrien's father, refusing to allow her to have any friends and telling her she can't do art because drawings are terrible despite Tomoe being blind. As a result Kagami is hyperfocused on her fencing and other stuff her mother makes her do, and has zero social skills (as shown when she awkwardly tries to make friends with Marinette). Making things worse is that Adrien's attraction to her has given her the ire of Chloé and Marinette, as well as Shipper on Deck Alya. In "Ikari Gozen" Kagami sees a disparaging video from Alya and realizes that Marinette disliked her, not accepting her friendship. Despite Marinette's attempt to humiliate her, she still keeps her cool, although is clearly saddened, but at least the two become friends at the end of the episode. When she starts dating Adrien, he's constantly blowing her off due to having to be a superhero, which causes her to break off the relationship. Even in season 4, Marinette is stated to still be her only friend.
Adrien, who is a Stepford Smiler about his home life, does a suffocating modeling job to make his dad happy but leaves no time for him to hang out with his friends, and crushes on a Magical Girl whom he thinks is better than he is and rebuffs his romantic gestures. Heck, in his birthday episode, "The Bubbler", only one person remembered to give him a present and his best friend got turned into an akuma on his behalf.
Marinette. She's bullied at school constantly (by both Chloé and Lila), she has to deal with the fate of Paris constantly resting on her shoulders as well as her normal, also stress-inducing responsibilities on a daily basis with little to no free time, and she has to deal with her clumsiness and constant heartache over Adrien on top of that. Is it any wonder she ultimately breaks down during the season 3 finale? In season 4, she breaks up with Luka despite genuinely loving him, and in "Gang of Secrets" has to constantly lie to her friends, and breaks up with them, causing her to break down further.
Nooroo, the kwami of the Butterfly Miraculous, is enslaved by Hawk Moth and forced to aid him in a terrorist campaign against Paris. His relationship with Hawk Moth is routinely shown to be emotionally and occasionally physically abusive; he is forbidden contact with the outside world, not allowed to be more than a few feet away from Hawk Moth, yelled at whenever he questions his master's decisions, and he has had his mouth magically shut on two separate occasions when he has truly angered Hawk Moth. Finally, he is completely powerless to save himself and can only wait for Ladybug and Cat Noir to bring him salvation, and with the reveal that there's still a Hawk Moth active in the future in "Timetagger", it doesn't look like that will happen anytime soon.
Zoé is Chloé's half-sister, sharing the same abusive mother. She was raised in the United States. There she only had one friend but was otherwise bullied by her classmates, who even put a cockroach in her locker. When she moves to Paris, Chloé makes her put on a Jerkass Façade and orders her to throw away her shoes that her friend signed, which leaves her in tears. She thankfully manages to make friends at the Collège Françoise Dupont. Despite how her sister treats her, she is trying to start a loving relationship, but Chloé says she will always just hate her and swears revenge at the end of "Queen Banana" and uses her as a human shield in "Optigami".
