First I have to mention the cast. This cast makes me want to go back to my previous reviews and reduce the star rating I've given to other dramas' casting. The casting in the drama is SOOOOOO GOOOOOOOOOD!! I wish there were a once-in-a-decade "11 stars" option. Every single role was cast perfectly and the actors were perfection in their roles. Seriously, I have never watched a better cast drama than this. And a special shout out to the dude who played the emperor. He was an absolutely delight and perfect in his role.
I'm writing this review after watching part 1 and 2. If I'd written this before watching part 2, this would've been a 10/10 drama. As it is, and after watching the second part, I now see the flaws in the story of this show and it is no longer a 10/10. More details in my review of part 2.