Based on the comic "TrappedSoul" by shishitsunari on tumblr
Ladybug snapped the akumatized flashlight apart, the darkness seeping out until a black butterfly flew out, attempting to get away before it could become pure again.
Just as Ladybug's hand flew for her polka-dotted yoyo, Chat Noir grabbed the butterfly, enclosing it within his hands. Ladybug could only stare, mouth agape, as sparks of electricity shot out of Chat's enclosed hands as he absorbed the negative energy within the akuma, breaking his fists apart as soon as the task was done.
"Chat Noir, stop that!" Chat turned his head slowly as Ladybug, his Lady, continued, "this isn't you! It's-this! Thisis all my fault! It is not your duty to purify the akumas, you weren't chosen to do that! This is dangerous! I should've never let you do it the first time! No one should be absorbing so much negative emotions…absorbing all these akumas is changing you, Chat! Please, leave the purifying to me! You're not acting yourself!"
Chat stood there for a moment, frozen in shock at what his Lady had announced, turning to glance at her, his green eyes bright with anger, before he shot across the rooftops, embracing the cold wind stinging his cheeks, eager to get away fromLadybug, to get away from what she was talking about. He ignored the "WAIT!" that reached his ears. She was speaking nonsense, the akumas weren't affecting him, and besides, after he took away the negative emotions out of the akuma, it could not be akumatized again, thus rendering the butterfly useless to Hawkmoth. Why was she trying to stop that?
Far away, he heard his name murmured sadly, as if it would bring him back to her.
"Nothing is better than a good piece of cake!" said a little red creature with a huge black dot on her forehead and two more on her cheeks, munching on a small cake slice. "After this, I'm sure to be able to get back into action!" The kwami stopped eating as she realized she had gotten no reply, not even a noise, in response to her talking. She flew over to the kwami's charge, immediately feeling the negative aura surrounding her.
"Marinette…? What's happening? You seemed so energetic a couple of minutes ago, what's wrong?" When all the small red kwami got was a small glance full of devastation before continuing to look at the small circle with a gear design Marinette held nimbly between her fingers, the kwami knew what was affecting the young dark-haired teen.
"Marinette, we're going to find him, and then you can patch everything up!" the kwami said in what she hoped sounded like a cheerful tone, but it didn't so much as dent Marinette's sad aura. As the red kwami started to float down to the desk in front of the teen, she heard a voice so quiet she almost didn't hear it
"I had imagined finding out to be so different, to be…happier, Tikki." The small kwami glanced up at her name, only to find Marinette's broken face, and Marinette's voice cracked as she continued, heavy with emotion.
"For a moment, I had thought that maybe I wouldn't be so bad if Chat turned out to be Adrien..I had liked both of them, despite the fact that were weren't so similar to each other; Chat was loyal and, yeah, funny…meanwhile, Adrien was so kind, and altruist…. After I came to better understand Adrien, I saw more and more similarities between them and…I liked it!" she threw her hands up in exasperation and laughed, but her laugh was not at all kind. "I thought, maybe he would reveal himself to me, maybe he trusted me that much, and…oh, I don't know, maybe…it would be some kind of confession, because Chat already like me-I mean, Ladybug-I think…then arrived the akumas, ruining everything…they both changed…it couldn't be a coincidence, like….how they both are allergic to pigeon feathers, or Adrien's strange interest on everyone's opinion on Chat…" The teen paused for a shuddering breath, and it was apparent she was on the verge of tears. "it couldn't be a coincidence.." she repeated. Marinette shuddered as a memory rose to the surface.
Nino, Adrien's best buddy, had barely gotten "Adrien, ca-" before getting cut off by Adrien shoving his elbow into Nino's chest, not hard enough to hurt, but enough to alarm Nino as a worried look took on his face, prompting him to ask the blonde "Are you okay?", which only got a glare from dull green eyes, normally so bright and joyful, rimmed by dark bags.
"Marinette…" Tikki spoke softly, knowing how careful she had to choose her words, "there's…." the kwami sighed, her whole body moving. "There's something I have to tell you...I've-I've always known known that Adrien was Chat Noir…" Tikki fiddled with her stubs-for-hands as she explained, "I sensed Plagg's-Chat Noir's kwami-presence in your classes every day. He's always been in Adrien's bag, so it wasn't hard to put two and two together."
Tikki was scooped up by Marinette's shaky hands, and the kwami looked up at Marinette, whose expression was unreadable, before continuing, "we spoke in arm gestures, oh, we'd talk about all sorts of things to pass the time. We talked about you two quite a lot, about your battles, misunderstandings, and such. But that is not the only thing you need to know…Chat Noir never mentioned it because he respected your wish to keep it secret, but...he knows…he has known for some time now.." Marinette didn't try to stop the tears that she had been trying desperately to hold back, as they fell silently across her cheek. Tikki's heart broke at the sight, but she continued, nonetheless. "He had secretly decided to protect you as both Chat Noir and Adrien. Adrien had found out purely by accident, when the two of you had fought Dreamwalker.
"Remember when you fainted, Marinette? He had stayed with you after your transformation wore off to make sure that you were safe-" Tikki was cut off by a sob from Marinette, who had lifted one hand to cover her mouth as tears were violently streaming down her reddened face. "Oh, Marinette…" Tikki floated to stroke her charge's face, soothing her while the teen wept.