I have the perfect AU for Monochrome.
Ratings: anything but I'd say explicit
Blake Belladonna
A mysterious Faunus who doesn't particularly keep anyone close or far away from her. Is into literature and strangely, blades. Doesn't cause trouble, is always at the library, and most people don't really know who her family is because she come from a different kingdom.
Her family is plenty wealthy from the southern kingdom.
Weiss Schnee
A quiet heiress who is incredibly intelligent and hard working. Is musically gifted. Everyone wants to be close to her for various purposes and none of them are good. Is a good student, every teacher likes her, loves staying at the academy's west wing where there is a piano and because nobody is usually there, everybody knows her family, the Schnee.
The Schnee owns the dust economy tightly, is the most influential company in the northern kingdom.
Fanfiction trope: enemies to lovers
AO3 Tags: "I hate you. I hate you so much. Kiss me. Please.", rough making out session against the bookshelf in the corner of the library, right after they spit insults to each other's face, a long game of push and pull, and denial, full of spitefulness, so much angst you will scream, cause; overwhelmed, add some spicy scene, Weiss's skirt stays on during all of that, Blake growls, snarls, hisses, and many more unspeakably sexy noise, it's about the pining, it's so painful you almost can't keep going, one of them break into the other's dorm room at night, it was Blake, and they cuddled, begrudgingly they said, we know they enjoyed it.
It's just really hot, with a dark aesthetic, the 1930s vibe, less focus on real-world drama, more about the pining, and the hatred so great they make each other feel everything.