Greedling aka Chadrien/Adrichat
A concept:
ML but with Adrien Agreste having Chat Noir, a separate entity, the very definition of destruction, inhabiting his body.
Similar to Ling and Greed from Fullmetal Alchemist.
Adrien basically makes a deal with the devil god of destruction Chat Noir to be able to do things he wants to (gain freedom) and protect his loved ones. So he and Chat Noir share a body and switch sporadically whenever the other wants to.
Chat Noir, since he's mischievous and a troublemaker, likes to switch whenever its inconvenient for Adrien.
I.e.
Adrien talking to Marinette about homework.
Switches over to Chat Noir, leans seductively against wall with a rose in his mouth:"You know princess, we could do it in my room, huh?" *wink*
Marinette, double innuendo not lost to her: " *Marinette.exe has stopped working*
Ahem...
Adrien, listening to his father lecture him about not going out with his friends for ice-cream.
Chat Noir, shoving Adrien to the back burner of his soul and pupils narrowing into feline slits. "Oh yeah? Sorry old man, but if I want to go out for ice-cream, then I will."
*exits*
Gabriel: "....Nathalie?"
Nathalie, adjusting glasses: "Yes, sir?"
Gabriel: "...Did....did he call me 'old man'?"