I've got an AU idea.
Instead of Adrien getting the black cat, Lila does.
"What!?" I hear all anti-lila people screech, let me explain.
Lila has been in Paris for roughly a month as her mother gets their home set up.
Lila's been left on the wayside by her mother (as usual) and generally takes long walks around the local area when she's not being homeschooled
It's on origins day that, while out for a walk, she instinctively saves Master Fu from a nasty fall.
He reminds her of her grandfather, who she loves dearly.
She shrugs off the encounter and gets back home, left alone once more while her mother spends all her time at the embassy.
All in time for Stoneheart to attack and then finds the ring in its box on her desk.
Learning that she was going to be Paris' new hero was... Quite a shock.
But she quickly embraced the role right out the gate cause... Hello? What the hell else is she to do when left alone all day?
Of course, Lila is a liar, has been for a long time.
Originally a means to not receive unnecessary punishment from her mother had bled into her daily life.
Reflexive lies to looks good or avoid punishment's had turned into gaining popularity and fame.
Ladybug, does not like it when she lies, as she has found out... Many, many times.
Despite embracing her role as Paris' hero and gaining fame daily, she still feels the need to lie to look even better.
It causes some strife between the two girls and Lila does sometimes quip that the two of them are perfect opposites.
Good luck - Bad luck, Honest - Liar, Creation - Destruction. A disaster bug - a cool Cat.
That last one earns her a wack on the head via a yo-yo.
During all her spare time Lila is walking around as either herself or her hero persona.
She frequents the Dupain-cheng bakery cause... While she can't afford Camambert like plagg want's, she can get a good supply of cheesy treats for him with her pocket money.
Said pocket money, being what her mother counts as a replacement for affection and good parenting.
Lila never sees a problem with her lies until the day comes she has to join Dupont.
Her small lies do get her some fame and her (actual truth) lie about being ladybugs BFF gets her a lot of fame.
Plagg had warned her against saying it but shes a little too stubborn and chaotic to listen.
Plagg points out the book Adrien has and says it's something related to the miraculous and he should try to get it.
She does but doesn't see marinette watching her and before she knows it she's at the park talking to Adrien cause she has a gutt feeling Adrien is somehow involved with hawkmoth.
That is when ladybug comes from nowhere and debunks the (terrible) lies she had made... And... She's never seen LB so mad before.
And it's directed at her.
There is no Volpina akuma, plagg just destroys the Akuma as it comes for his chosen.
But she does stew for a little while before taking it to Ladybug. Where she then goes off with it to do who knows what.
And from the on... She's determined to do her best to stop lying.
Even if it means coming clean to the class and embarrassing herself.
What's she supposed to do? Stay away for months? Her mother would never let her.