King's love in the start went flawless and i enjoyed it to the core, from the cast to the soundtrack and everything. Im Siwan doesn't disappoint at all in the role of a young crown prince, having a deranged father and an overprotective mother. Due to the strained relationship b/w the father and son, he finds love and haven in the company of his one and only childhood friend Wang Rin. Their friendship was their armour which kept them together in all odds of life.
Lady eun San on the other hand seems bold and strong woman who enters their lives and that's when the trio is built.
The first half of the drama was interesting as we see how each character evolved from weaker to a stronger personality. What annoyed me is that after the first half of the drama ended, there was so much chaos in the plot that it was unclear which track the drama is following. The plot was completely twisted and the emotions of the characters were so unclear that even though the drama ended, that unsatisfying feeling still lingers. I almost felt like dropping it because even though it wasnt a cliché like other dramas yet it creates so much uncertainty and frustration among us, the viewers that we couldn't decide if we should continue watching it or not.
Hong Jung hyun was unexpectedly good and fits in his role. His devotion for the crown prince as a friend was the only thing that made me watch it further. I hated his character in scarlet hearts ryeo so much that I didn't know that his character in this saguek will completely wash away his character from the previous drama. More than the love b/w any of the leads I ship WonRin more and maybe that was one of the reason I continued watching it.
The most disappointing character of the drama was yoona who seems so fickle at times that her character completely lost the track and it was hard to figure out what she wants. All her hollow bravery and smartness faded after a few episodes when she transformed from a bold character to a damsel in distress with those teary eyes in almost every episode.
Also the writers seems to be a bit averted and confused  with the plot. They first make the villain justify the cause behind all his actions but later makes him a completely aberrant being who just seems to serve the powerful and wants to be a king maker. Song In's character seems to be portrayed as someone who cares for the common people and thus want to remove the powerful and ruthless Yuan rule but after a series of events he turns out to be a greedy mad man who only wants power. The only thing that I might miss about this drama is the bonding b/w the leads and the soundtrack.