Oh Na Ra is the queen regnant (QR). A brash and independent woman who always got her way which turned off any suitor because of her controlling and demanding personality.

Kim Byung Chul is the introverted scholar who has lived a monk’s life in the temple library. When he was called to the castle to resolve a dispute between the King (Kim Hee-Won) and QR, he sides with her logic and strong opinions. As a reward, the QR gives him a “pity affair” in her chambers which leaves him revolted and ashamed of himself for becoming in his words “a peasant pig.”

Lee Dong Hwi is the sensitive artist who only communicates in childish poems and (illegal) erotic paintings. In the capital, he is considered a worthless fool. He has a high libido but cannot pick up women because his gibberish poems are long and nonsensical. When he was arrested for trying to peek into the consort’s chamber for his art inspiration, guards raid his house to find his illegal paintings. The King wants to behead him, but the QR wants instead a portrait of herself commissioned by the palace. In her study, QR began to model for the painter but she slowly begins taking off pieces of her royal hanbok. The resulting fallen easel linen is splattered with ink as they coupled with crude abandon.

Kang Hong Suk is the Sujongjang (수정장), Deputy gatekeeper at the palace. Every time the QR passes his station, she winks at him, or licks her lips, or blows a kiss to him. It causes trouble with the Chief gatekeeper, Park Seo Joon, who is a strict class caste system advocate, who wants to show his extreme competence to the King in order to be promoted to Army General. Late one night, QR sneaks out to Kang’s post for a private, naked taekwondo lesson. The Chief finds out about the affair and wants to castrate and dismiss the deputy until there is a sudden announcement that the QR is with child.

Kim Do-Eun is the princess child. She inherited from her mother an unfiltered approach in dealing with people. She could be rude, crude, menacing (around the scholar) but also at times teasing, goofy and playful (around the artist) or lazy, melancholy, tearful and manipulative (around the Deputy Guard). In most respects, she has more common sense and survival skills than any of these potential fathers.

Lee Joo-Young is the young adult princess who really only focuses on the negatives of each potential “official” father. She secretly wants to spend her time with the King because he is kind, gentle and a pushover when she smiles after any request. She constantly gets into fights with her “fathers,” often ending each fight with the dagger phrase “I don’t know what my mother saw in you!”

The palace is filled with royals, noblemen and military officials for the Fatherhood Coronation ceremony. The King greets all the guests and introduces the three candidates to the crowd. (The Chief has been going around taking large wagers on who will be the winner so he can bribe his way to a promotion.) The...

Queen Regent: This one has Mishil written all over it so I'm gonna cast Go Hyun-jung.

Consort 1: Ju Ji-hoon.
Consort 2: Go Soo.
Consort 3: Bae Soo-bin.

I'm still trying to wrap my head around how she got 3 consorts in her harem. I'm just gonna think about this Mishil style cause I can't even start to make sense of this part.
And for our lovely princess: Since she's all grown now, I'll cast Go Yoon-jung.

I would like the princess to have a romance of her own as well.

As usual, I'll leave the casting to more experienced beanies. But switch the genders around? WHY? Never!!! The whole point that makes this "historically inaccurate" sageuk a hit, is the reverse harem. We've had so much of that "prim and proper" crown princess selection. Let's have fun choosing a slightly cracked widower princely father 👍😂

I'm just here to give a heartfelt shout-out to @mary for the invention of a term that we didn't know we all needed (but totally did):

candadate

Kudos, Mary!!

PS: Whoever is cast, I want it to be the case that the princess doesn't choose any one of the three men to be her "father" in the end, but instead accepts them all as her loving and guiding lights who accept her and her strengths, each in their way.

Queen: Honey Lee (just because)

Consorts: Joo Ji Hoon (got the idea from jerrykuvira), Yoon Kye Sang (kidnapping day reunion), Park Sung Hoon (because I need him in a non-villain role)

Princess: Yuna she is the right age for the teenage rebellion. If she gets older maybe Kim Hye Yoon can play the role

Kim Nam Gil for artist!!! Choi Jin Hyuk for scholar. Lee Dong Wook for fighter. just try and pick only one, bc they bring out the best qualities in these characters. Kim Nam Gil can be soft but goofy and yet kinda reliable, Lee Dong Wook is passionate and convincing bc he has that charm, you cant say no, but he is perhaps overconfident. and Choi Jin Hyuk is just so sweet and innocent I feel like a princess would grow the most fond of him (by babysitting his dad and saving him from trouble bc he can´t fight) Lee dong wook say she doesnt need to learn how to read only kick bad guys in the balls. and besides art she learn the most necessary life skill from Kim Nam Gil: how to count and save money / be resourceful. because artists are no romantic dreamers we are the most realistic people always accounting & keeping out the antenna for extra income. so she also learns how to rely on herself and make money with a lot of things from him.
Queen - Han Ye Ri! though, sry girl for doing you off again. she keeps on dying everywhere.
and the girls from Day of Kidnapping could play young princess and Kim Yong Ji the older one. dont know if she has the chops but she can defo do any fight scenes

I have an inkling that @mary has been inspired by 1 Mom & 3 Dads! 😁

I envision this as a sort of Joseon Three Men and a Baby. The three potential dads, each claiming paternity, end up moving in together in an awkward co-parenting arrangement. They argue over the proper way to raise their darling and compete to win over her affection. There are the expected squabbles over housekeeping and personal habits—Consort #3 is the sloppy "Oscar Madison" to Consort #1's fussy neat freak "Felix Unger." (Giving away my age here with the Odd Couple reference.) Meanwhile, our sassy Little Miss knows exactly how to play her three dads against each other to rule the roost.

We get flashbacks as each daddy candidate relives his steamy encounter with the Queen, as well as scenes during the pregnancy where she tells each one that he's the father. Her ultimate goal is to provide her baby with three staunch protectors, each of whom brings a special quality as a parent: the intellectual, the artist, and the fighter.

The three dads lay aside their differences and come together to protect their darling from the Queen's enemies (led by the Queen Dowager and the Left Minister, who bribed the royal physician to slip the queen some poison and give out that she died in childbirth).

As far as casting, I propose:
Lee Se-Young as the Queen Regnant
Go Kyoung-Pyo as Scholar Consort
Jang Dong-Yoon as Artist Consort
Yun Kyun-Sang as Soldier Consort