Marinette's Purr-fect Pet

Prologue

That Cataclysm. It was unlike anything she's ever seen before. It looked like it could destroy... everything. Just like Cat Blanc wanted. But she honestly couldn't blame him. From what he was saying, he lost everything. His love, his friends, even just someone to talk to. All gone.

She's tried everything to get through to him this whole fight. But he wouldn't listen. Or he couldn't. He only wanted her miraculous, because he thought it was the only way to-... "Wait, Cat Blanc, there's another way!"

Hesitating, the Cataclysm stops growing. "What are you talking about?"
Ladybug steps forward slowly, hands outstretched, like she was approaching a frightened animal. "The wish... I can't let you use it. But there's another way for us to be together."

The akumatised hero growls and the Cataclysm in his hand grows bigger. "I won't let you de-akumatise me!"
Ladybug raises her hands. "And I won't, I promise. Just put the Cataclysm away, and let me explain." Blue eyes glared at her, pupils narrowed into feline slits as the white glow in his hand faded into nothing.

Sighing in relief, Ladybug talks quickly. "We need to keep Hawkmoth from akumatisimg you in the present- er, the past? You know what I mean. Bunnix can help. She brought me here. I can fix everything, just like you wanted. No wishing, no sacrifices needed. I just need to know, how did you find out my identity?"
Cat Blanc looks down at his clawed glove with a nostalgic smile. "You gave me a gift. I saw you leave as Ladybug. But the beret, it was signed... Marinette."

Ladybug's eyes widen as she realizes several things. First, she now knows what the eraser is for. Second, the secret identity of Cat Blanc, and therefore Cat Noir, was- "Adrien?" Tears pool on the corners of her eyes and she presses her spandexed hands to her mouth in an attempt to not cry, laugh, throw up, or a horrific combination of the three.
The white cat bows with a smile. "At your service My Lady." Rising, the smile is a little strained. "You said you could fix everything?"

Forcibly pulling herself together, Ladybug nods. Taking a deep breath, she whispers to herself. "I really hope this works. BUNNIX!"
A portal appears near the duo and the rabbit themed hero pokes her head out. "What the hell are you doing?! You were supposed to de-evilize him!"

Ladybug shows her the eraser. "I know what to do! I can fix it!"
A white hand gently lands on her shoulder. "Where My Lady goes, Cat Blanc goes."
Looking between them, Bunnix tries to argue. "You can't do that! Time is serious stuff! You can't just- aaaghhh!" She's cut off by her body flickering. "Grrrr. Alright fine. But you better keep him on a leash while he's there."

Racing to the past, Ladybug stops her past self from signing her gift to Adrien. "Trust me, it's better this way." With the message erased, she throws the Lucky Charm in the air. "Miraculous Ladybug!" The magical ladybugs fly through the air and the portal left open behind her and Cat Blanc, merging the two Ladybug's together, and if the portal closing is any indication, fixing the universe enough for Bunnix to be satisfied. But there was one problem.

Ladybug stares solemnly at Cat Blanc. "You're... you're still here."
Cat Blanc looks at his hands, like he's surprised too. "Yeah. You erased the message, but my memories... they haven't changed."
"It must be because you're still akumatized." She reaches for Cat Blanc's bell, the only thing that the akuma could be hiding in, but the akumatized hero grabs the bell, not letting Ladybug touch it. "So if you de-akumatise me, then the next time you use your Lucky Charm, Adrien will..." he trails off, letting Ladybug fill in the gaps.

"He'll... remember." Tears fill her eyes and she holds the inverted hero. "I'm so sorry Adrien."
Clawed hands hold her more gently than anyone else ever had as he shushes her. "Shhhh. It's ok Marinette. It'll be fine. I'm ok now." At least that much seemed to be true. Stuck in the past, no longer the sole living thing on the planet, and now holding her, he seemed to regain some semblance of sanity. His white leather ear twitches. "He's coming. I can't be seen. I'm sorry, My Lady. I'll see you at home." Letting her go, he leaps out the window as the door to Adrien's room opens.