Ratiorine/Aventio Mirror AU where Ratio is part of the Genius Society and Aventurine is a Masked Fool. Yes, I know it goes against the point of their characters, Ratio's especially. However, what if we took the other core aspects and reapplied it to the new background and context?
Genius Society member Dr. Ratio whose love for humanity manifested differently, enough to get a glance from Nous. Genius Society member Dr. Ratio who believes in humanity so much that he pursues knowledge in its rawest form knowing that someone somewhere will eventually pick up the pieces of his research and do something with it. Genius Society member Dr. Ratio who searches for the untarnished truth, who studies all the intricacies of subjects most helpful to humanity, who lays down the foundation of objective information for future scholars to build off of. Genius Society member Dr. Ratio who is a utilitarian when it comes to the good of humanity, who lets the passage of time bring him the fruits of his efforts, who makes necessary sacrifices for the greater good.
Masked Fool Aventurine who accepted the Tavern's invitation, whose thirst for survival manifests in the manner of technicalities. Masked Fool Aventurine who seeks the thrill of living in the present, seeks hedonistic pleasures in daily life, makes big gambles just so he can feel the rush of exhilaration with every win. Masked Fool Aventurine who lives and dies and is reborn with every new identity, with every mask he puts on, with each different name he wears. Masked Fool Aventurine who impersonates all the people he's lost in hopes of seeing them alive one way or another, who plays into his stereotypes so that even small remnants of his roots survive (even in the ways that aren't fun, because negative attention is still attention). Masked Fool Aventurine who loses himself in the frivolities of a fool, who slowly forgets his original name and face.
It all starts as a game, at first. You know, those stuck-up geniuses are so fun to mess with. They're so uptight and serious, can't they just lighten up a little? Ah, but they're not immune to nonsensical antics. For the quintessential component of a scholar is curiosity, and the most curious thing to a genius is the mind of a fool. Just like that: hook, line, and sinker. The masked gambler reels in the good doctor, who had been following his little trail of clues all this time...
"I finally caught you, gambler."
"Hah, as expected of the esteemed doctor. It didn't take you long to figure me out."
"You've made yourself into quite the enigma, though it is one not impossible to solve for someone like me."
"Of course, of course. Now, why don't you put that oh-so-intelligent brain of yours into solving something else instead?"
"What do you mean to imply?"
"A genius's job is to discover the unknowns, is it not? I wonder... if rediscovery is on the agenda, too."
"With time comes the inevitability of outdated data or newfound truths. I suppose it is not out of the question, depending on its purpose."
"What if the purpose was something... selfish?"
"It would not faze me, for it is nothing new to me."
"My, how scandalous! Well then..."
"You fool, what are you—"
"My original face and name. Can you find them for me, darling doctor?"