The cast was great. I felt like they all fit the character except the gatekeeper of Samdo; she gave too many mixed signals. The storyline was kinda slow especially near the end. I watched it as it aired but I would have dropped it at episode 12. I honestly only finished it so I could mark it as "complete." The ending was redundant and I wouldn't even be mad if they let Lee Yeon perish. They had to make it a good ending so they put way too many twists. At this point, I just felt like the characters were just sacrificing lives back and forth to revive other characters. It had such a great build-up/rising action but the ending was redundant and unsatisfying.