I'll write about the story, cast, music, rewatch and overall value.
Story:
This story is not for everyone because some people dont like mythical show so this not for you but give it a shot. Trust me i never regretted the decision of watching this. It hooked me from episode one. Definitely needs to release season 2.

Cast: Song Joong ki never fails to deliver i mean look at Descendants of the sun or Vincenzo. He acted both his roles great. He had two completely different personalities for both his characters and id actually think it was another person acting the role because he was that good. Who cant get enough of him though???Plus i cant forget my girl Kim Ji Won, i loved her in Descendants of the sun and am happy to see her be a lead role with Song Joong ki. She has talent and potential to be even better (not saying see hasnt reached her potential but that she has higher potential to unlock)

Music: not alot of music but it was great nonetheless.

Rewatch: i have already rewatched this over ten times and i am not exaggerating. It is literally my cup of coffee (tea)

Overall: this is a must watch, dont stash it in your watch list for years, WATCH IT NOW!!!