Not much is known about Lila's early life aside that she was born in Italy and that her mother works at an embassy. She enrolled in Collège Françoise Dupont in Paris, France as a transfer student.
In "Volpina", Lila went to her first day of collège, told several lies about herself to other students, and was interviewed by Alya for the Ladyblog, in which she stated that Ladybug had saved her in the past and that they are close friends. She met and became infatuated with Adrien, but later, she discovered his feelings for Ladybug when they're with each other in the library. Stealing his book, she told him to meet her at the Place des Vosges that afternoon. Before heading there, she bought a necklace resembling the Fox Miraculous. At the park, she told Adrien that her grandmother was a vixen superhero named Volpina and that she had passed the Fox Miraculous on to her. At this moment, Ladybug appeared and began to yell at Lila, calling her out for her lies and causing her to leave in tears.
Lila was then akumatized into Volpina by Hawk Moth, who gave her the "power of illusion." In order to draw out Ladybug and Cat Noir, Volpina created an illusion of herself stopping a meteorite and saving Paris. Then, she asked Ladybug and Cat Noir to help her, tricking them into chasing after an illusion of Hawk Moth. She drew Ladybug and Cat Noir apart from each other and then accosted Ladybug, threatening to destroy a building if she refused to hand over her Miraculous. Ladybug almost did, but she realized that everything that had happened had just been illusions, and figured out Volpina was an akumatized Lila. Volpina escaped and went to Adrien's house, telling Adrien that she hadn't been lying earlier. After Ladybug and Cat Noir showed up and fought her, Volpina went to the top of the Eiffel Tower, creating an illusion of Adrien and threatening to drop him from the Eiffel Tower if Ladybug didn't give up her Miraculous. After this too was revealed to be an illusion, Cat Noir used Cataclysm to trap her, and Ladybug captured her akuma, turning Lila back to normal. Ladybug tried to apologize for her actions earlier, but Lila refused to accept the apology, claiming that the two of them would never be friends.
In "Sapotis", she was briefly mentioned by Alya when she finds her new superhero outfit looks similar to Lila's akumatized form. Ladybug explains that Alya nevertheless is a superhero now and takes off, with Alya happily following behind her.
Lila appeared in archive footage in "Queen Wasp" of her appearance at the fashion show in "Style Queen".
In "Catalyst", Lila video chats with her classmates and claims to be in the Kingdom of Achu, though really she is just hiding in her room. She tells them that Prince Ali invited her and her parents to his palace. Marinette, aware of Lila's deceitful nature, attempts to expose this lie by pointing out that Prince Ali is in the USA, but Lila uses her wit to maintain her deception. Miss Bustier asks Lila what she has prepared for Heroes’ Day, to which Lila claims is a pollution-reduction project. After hanging up, her mother bursts into her room and asks who she was speaking to. Lila claims that it was her boyfriend Adrien. Lila's mother then asks about the school, which Lila claims is closed from all the akuma attacks. When Mr. Damocles calls Lila's mother, Lila convinces her not to answer it by telling her that the principal was akumatized. Later on, Lila scrolls through a bunch of news feed about Ladybug until coming across an interview with Gabriel Agreste and Nadja Chamack. In it, Gabriel says that he has financed a film about Ladybug and praises the herione, saying that she is the only true hero and dismisses "imitations" such as Volpina. The comment about Volpina drives Lila over the edge, and she angrily throws her laptop against a wall and proclaims her hatred of Ladybug. Hawk Moth senses Lila's anger and sends an akuma after her, which infects her wristbands. Hawk Moth offers her the power of illusion to make Heroes' Day a nightmare for all Parisians. Lila accepts the deal and is once again transformed into Volpina. She goes to the Effiel Tower and creates an illusion of an akumatized Ladybug fighting Cat Noir and eventually destroying him with his own Cataclysm, causing massive panic throughout Paris. Hawk Moth commends Volpina for a job well done and promises that they'll see each other again real soon before removing her akuma. Lila smirks as she watches her akuma fly away.
In "Mayura", Lila is shown to be once again akumatized into Volpina by Scarlet Moth. She tricks Ladybug and Cat Noir with an illusion of Scarlet Moth while the real Scarlet Moth attempts to sneak attack behind the duo. However, the plan is foiled when Ladybug spots the real Scarlet Moth through her Lucky Charm's reflective surface and Cat Noir destroys Scarlet Moth's cane, reverting him back to Hawk Moth and deakumatizing all the supervillains, Volpina included. She is last seen angrily watching her classmates have a picnic from her bedroom window.
In "Chameleon", Lila returns to Miss Bustier's class. She tells her classmates that she has tinnitus and needs a front row seat so that she can sit next to Adrien. Then at lunch, she claims to have a sprained wrist and tricks her classmates into getting her lunch for her. Marinette, who is aware of Lila's deceit, attempts several times to catch her in a lie, only to fail each time. Lila notices that Marinette does not seem to like her and confronts her about it in the bathroom. She believes that she is jealous because she is sitting next to Adrien and says that it's not worth it to fight over a boy, even offering to be her friend. However, when Marinette reveals that she is aware of Lila's lies, Lila drops her friendly facade and gives her a choice: either be her friend or she'll turn all her friends against her. She then bumps into Adrien and asks him to help her catch up on her schoolwork as well as give her piano lessons, claiming her uncle is a famous pianist who tried to teach her but she had to stop due to arthritis.
However, Adrien is aware that Lila is lying and advises her to stop, though she merely becomes annoyed with him and walks off in a huff. She then spots an akuma and allows it to infect her earring. She greets Hawk Moth and asks him to give her supervillain powers in exchange for Ladybug and Cat Noir's Miraculouses, to which Hawk Moth agrees, turning her into the villain Chameleon. As Chameleon she approaches Adrien and pretends to have taken his advise about honesty, only to then kiss his cheek, steal his appearance, and make him fall asleep. She stuffs Adrien inside his locker and then approaches Alya and Nino. Pretending to be Adrien, she tells the latter that he doesn't deserve his friendship, his girlfriend, or his cap stealing it and took off. Ladybug witnesses this and follows Chameleon, who creates havoc throughout Paris and then pretends to nearly fall off the Eiffel Tower. Ladybug catches her and Chameleon tries to "thank" Ladybug with a kiss, only for her to recognize that she isn't Adrien. The two briefly fight, and Ladybug grabs her cap, believing that's where the akuma is, only to find nothing.
During this, Chameleon escapes and takes the form of a boy named Quentin. Upon spotting Ladybug, she tells her that she saw an akumatized villain by the merry-go-round. While Ladybug is distracted, Chameleon attempts to sneak behind Ladybug, only for the boy's mother to show up and thank Ladybug for finding her son. Chameleon jumps towards Ladybug and attempts to kiss her, only for Cat Noir to jump between the two and take the hit instead, putting Cat Noir to sleep and making Chameleon take on his appearance. Before she can take his Miraculous, Ladybug interferes, so she instead calls on Cataclysm and attempts to use it on Ladybug while also trying to kiss her. When Ladybug takes off to the Eiffel Tower, Hawk Moth tells her to take Cat Noir's Miraculous, but Chameleon instead goes after Ladybug as she wants to take away her Miraculous first. When Ladybug's Lucky Charm gives her a T-shirt, Chameleon mocks it and continues to fight her. However, she ends up getting tricked into using Cataclysm on the ground below them and then kissing an oyster, taking on its appearance. Once Chameleon is defeated, Lila pretends to accept Ladybug's peace offering and advice about honesty, though once she and Cat Noir leave, Lila makes it clear that she hasn't forgiven Ladybug and won't listen to her advice.
Once arriving back at school, Lila continues to lie to her classmates about her friendship with Ladybug and having tinnitus. When classes resume, Lila is surprised when Adrien sat with Marinette in the back row instead of next to her. When Miss Bustier makes Marinette sit in the front row, in order to avoid sitting next to her, Lila told her teacher that Ladybug cured her tinnitus and she no longer needs a front row seat. Therefore, she sat in the back with Adrien. However, this causes a bunch of other students to want to go back to sitting where they were before, and Lila ultimately winds up seated next to Nathaniel. After school, she confronts Marinette, saying that she's made her decision and from now on, the two of them are at war. She vows to make Marinette lose her friends and make Adrien hers, though when Marinette responds calmly to her threats, she walks away in a huff.
In "Oni-Chan”, while getting ready for school, Lila received a message from her mother informing her that she will be home late but will try to be there for her over the weekend. While walking to school, Nino notices that she looks sad and asks her what’s wrong, but Lila convinces him that she is only upset because her mother had invited her to a fancy embassy function but she had to turn down the invitation due to all the homework she has as a result of missing so much school. Also claiming that Adrien had offered to help her but she doesn’t want to bother him with it as he may think she’s got a crush on him, therefore getting Nino to ask Adrien for her. When Adrien approaches Lila and offers to help her, she happily thanks him and, after noticing Marinette spying on her, suggests they work at his place, though he disagrees since his father doesn’t like visitors. However, Lila believes that she can change his mind. She manipulates Adrien’s bodyguard into letting her into the car and once they arrive at the mansion, she manipulates Nathalie into letting her in by claiming that Adrien needed help with his schoolwork. Once inside Adrien’s room, Lila begins snooping around and becomes jealous after seeing photos of both Kagami and Ladybug. Lila was informed by Nathalie that her time is up, she took a photo of her kissing Adrien before leaving, which she immediately sends to everyone in the school, including Kagami. As she was about to exit the mansion, Gabriel spots her, who quickly proclaims that she was his biggest fan before rushing out. Outside, she spots Marinette buried inside a pile of trash bins and considers posting a photo of her on the Internet to humiliate her, but deems this as "too easy".
Walking home Lila was approached by Oni-Chan who forced her to renounce Adrien, and becomes further enraged as she continues to lie. Cat Noir then arrives and fights Oni-Chan while Ladybug helps Lila escape, although she is ungrateful and claims she can take care of herself. Oni-Chan manages to catch up to them and touches Lila with her sword before she runs away, stating that there was nowhere she can run from her. Lila manages to stop Roger Raincomprix and convinces him to help her, and afterwards notices that a red horn is forming on her forehead. Then, Roger checks his phone to see a strange message, which causes him and Oni-Chan to switch places.
Lila runs out and tries to get help from Sabine Cheng in her bakery, only for her to also swap places with Oni-Chan upon checking a strange message on her phone. As Oni-Chan is confronted by Tom Dupain, Lila escaped and lies to Ladybug and Cat Noir by claiming she now trusts them, causing her horn to grow. Ladybug switches place with Oni-Chan after checking a message, which causes her to realize that Oni-Chan transports herself by sending messages to those near Lila. Oni-Chan again caught up to her when she runs away and tries to force her to renounce Adrien, which she does, only for her horn to grow and gave away the fact she was lying. Told by Oni-Chan that the only way that will make her horn go away is if she gives up Adrien sincerely, and Lila responds that doing such a thing would be too hard for her, and that the only thing that could make her renounce him would be if she eliminates Ladybug for her. As Ladybug and Cat Noir arrive, Lila pretends to have hurt her leg and has the cat take her away, leaving Ladybug to be defeated and restrained by Oni-Chan.
Stopping a nearby Fire Captain and Cat Noir tried to get him to take Lila to the hospital. However after inspecting her leg she was told it was fine, Cat Noir then realized that Lila made him abandon Ladybug so that she would be defeated, which she denies doing, only for her horn to grow again giving away her deception. When she heard Cat Noir give the okay for the Fire Captain to swap places with Oni-Chan before she can take Ladybug's earrings. Following Ladybug's plan, Lila was brought back to Ladybug by Cat Noir, which caused her to receive one of Oni-Chan's messages, thus allowing them to swap places, leaving Oni-Chan restrained and open to being deakumatized. Afterwards Lila walked back home on her own. The next day, Lila tried to get Adrien to help her with homework again, though he chooses not to. Believing he was mad about yesterday she tried apologize but was told by Adrien that her lies had gotten Nathalie and his bodyguard in trouble and that he won't help her if she hurts the ones he loves.
Then, Lila received a call from an unknown person, who turned out to be Gabriel Agreste. She meets him at the former's mansion, where he voices his disappointment at her for coming into his home through lies and manipulation. Lila claims that she only meant well as Adrien feels alone due to constantly being kept from negative influences. Gabriel asks Lila what she’d do if she were in his place, to which Lila says that she’d allow Adrien to have a friend his age that can protect him from negative influences. Seemingly agreeing, Gabriel tells Lila that they will meet again soon and the two shake hands.
In “Miraculer”, as part of their plan to bring Chloé over to their side, Gabriel and Nathalie approach Lila at the park, where she thanks him for allowing her to protect Adrien but claims to be saddened by the people in his life such as Nino, Marinette, and Chloé. She also expresses irritation over the fact that Chloé constantly brags about being Queen Bee but says that Adrien couldn’t care less since he’s so perfect. However, Gabriel informs Lila that Adrien isn’t indifferent to Chloé as they’ve been friends since they were young and thanks Lila for the information before taking off. Jealous, she comes to school the next day and approaches Chloé, telling her that she was friends with Ladybug and has a magic command that calls her right away. Chloé appears jealous but brushes this off until Lila offers to share it with her, to which Chloé agrees. After whispering it in her ear, she told Chloé that if Ladybug doesn’t come to her with that, she’s not a true friend. However, the next day she was approached by Chloé who tells her that the command didn't work and convinced her that it did work since she’d spend the previous day with Ladybug.
In "Oblivio", Lila was seen in one of the bus seats on her class field trip return home.