The guy has like 30 concubines, but only likes or even tolerates the first one you see, who doesn't like him romantically at all because she was his former caretaker of sorts when he was a little boy. Childhood crush situation. The concubine is a good person, wants MC to get with Emperor bc MC says she admires him (because of his face LOL.) Emperor is also... despite pretty much being a horny teen he reads ...'books' kind of innocent in a way, he's not some kind of faucet of lechery and heartbreak. I don't even care about his harem, people just forced marriages and the harem on him, he doesn't care about them at all and MC cooly has power over everyone anyway 언닝ㅇ~ 멎져요~
So far the series doesn't go in a dark direction except for some assassination attempt plotline.