Greyling quickly finds that a suit is pretty impractical for fighting in and requests Nooroo help him change it after a few outside battles and close calls.
So the direction I think this goes is that Adrien behaves a bit differently when he’s in the fray. In a word: showy. Like you know that sort of free feeling when you cosplay? This is that for Adrien. He also incidentally lets his excitable inner weeb through. He behaves very much like Cat Noir as you’d expect, but I am serious about him being even flashier. Cats at least have some form of lithe coolness to them that butterflies just don’t have. And the removal of the suit really dresses down him feeling serious too. Greyling is, dare I say, excited to actually be able to physically help Ladybug, but when it comes to the two actually conversing his charisma absolutely checks out.
Speaking of Ladybug, she’s actually a bit taken aback by the similarities between Adrien and Greyling. Like Adrien, Greyling starts out as a distant and grave figure, and when she meets him this bleeds over until his seriousness almost completely dissolves. With Greyling, she actually does find it a bit off-putting at first since their situation is no less dire than before he stepped outside. She wasn’t expecting someone so bubbly! What happened to the Greyling she knew and loved?! As she warms up to this new side of him, she begins to see more of Adrien in him. Not that she actually figures it out! She isn’t even that suspicious and it’s the same kind of frustrating obliviousness we love the show for.
He’s got a bit of a magician/performer vibe happening, and he uses his sword-cane to fence. Loves that playful banter.
“Your dad would totally fire me if he walked in on this, you know.”
“And lose the greatest literal babysitter he’s ever hired? I don’t think so.”
Marinette strains her neck to look at Adrien petulantly; he looks over at her and cracks a grin.
“You’re slipping, Mari!”
As his serious facade melts, Marinette is suddenly acutely aware of how warm he is against her. She’s not sure she likes the feeling as her blood runs cold and her heart clenches. I can’t do this, she reminds herself sourly, and tries to go back to relishing in her friend’s company.
So I’m not feeling all that good today; I ended up recycling something I’d sketched earlier and colored and shaded it, hence the sloppy quality. Sorry guys. :(
But anyway this is Greyling’s and Ladybug’s first meeting! Not much of a meeting, huh? Ladybug gets hurt pretty bad by Tux and though she eventually fends him off with the help of a Greyling-possessed volpina, Greyling can’t help but feel as though something is still very wrong and makes the snap judgement to go see for himself. His intuition ends up being right on the money because as Ladybug calls for the Miraculous Cure, she passes out and falls off of the top of the building she was on. Greyling ends up catching her before her head can hit the rooftop below and though her battle wound is healed, she remains unconscious for a couple of minutes, with Greyling freaking out and trying to wake her up.
Ladybug thinks that Greyling has managed to send a second champion when she awakens, not recognizing him. How could she? All she has to go off of to this point is what her classmates tell her and what people submit to the Ladyblog, and neither account is terribly solid since they never actually get a good look at him.
But Alya, oh bless her, sends Mari a text a few minutes later absolutely FREAKING out over the pictures she got of Greyling cradling Ladybug on a rooftop. They’re distant but very clear. (”LOOK MARI IT’S YOUR FUTURE HUSBAND” ”BETTER MAKE A MOVE BEFORE LB SNATCHES HIM UP YOU’VE GOT SOME STIFF COMPETITION”)
Kwami swap with Papillon!Adrien (Greyling) and Chat!Hawkmoth (Tuxedo Cat).
By some misfortune of the universe, Gabe ends up with the Cat Noir miraculous in the first place and Ladybug, dispensed as the yin to his yang, is tasked with getting it back. Naturally, he wants her miraculous too and wreaks havoc all across paris to lure her out. He is ruthless with cataclysm. Ladybug has to grow up a lot quicker to handle a guy with the power of destruction trying to kill her, so Mari ends up being a lot more serious but very in control of her double life.
Master Fu recognizes that she’s in over her head when one day Tuxedo Cat comes out to raise hell and Adrien, a civilian currently sneaking out to go to school, has to step in and help. Fu sees his potential and gives Nooroo to him. Gabe being Tux is like “Shit I put my son in danger” and puts Adrien on basically full throttle house arrest. No matter! The butterfly brooch holder is a distance fighter anyhow.
Greyling is born. Kid, you are not subtle with your names. Anyway, the akumas now sort of work in reverse: whenever Tux attacks, Greyling asks civilians for their help sending him back to lick his wounds/better yet, get his miraculous.
And the important stuff: the love square. Ladybug, though grateful for the thought, is not a fan of Adrien risking his life to help her that first time, but after that doesn’t have much contact with him. Marinette and Adrien don’t interact much either to begin with. Adrien still obviously loves Ladybug (so selfless, brave, and kind). The mutually reciprocated ship is Greydybug: Ladybug slowly begins to fall in love with whoever keeps sending help to her when Tux attacks though she knows very little about him. Unfortunately, in this au, a reveal is a death sentence, frustrating any attempts at them actually getting together.
Adrien has a lot less of a facade in this au since his dad is even more distant. He sometimes acts out in non-malicious ways to try to get attention and ends up anonymously forging a camaraderie with Mari. Since he’s more in tune with his emotions, Greyling sometimes accidentally ends up possessing his heroes in his desperate desire to help ladybug (which we see about to happen here). He’s good at it but is constantly horrified when his transformation drops and he realizes who he is again.
Anyway I fully support Papillon!Adrien and yall should too.