The "waiting hundreds of years for revenge" plot has been done before, but I was very happy to go through this iteration because the cast looked scrumptious. However, a few aspects concerning the show preclude true enjoyment:
1. The story is actually rather slow -- although there is fighting and lots of dramatic dialogue, little actually happens that has any emotional resonance (esp. in the first two or three episodes)
2. POINT CONTAINS SPOILERS:
SO MUCH of what happens, and some of the major dramatic turning points, make the main characters seem like complete simpletons. For example: The main character goes through hundreds of years thinking that one monster killed his family and it turns out that it could be another one. Really? For hundreds of years this assumption was not checked? In episode 9 the Other Bulgasal becomes incapacitated by our heroes WHO THEN JUST LEAVE HIM THERE. Really? How about restraining him and taking him along SINCE YOU WANT TO FIND OUT INFORMATION FROM HIM AND WILL TRY TO CATCH HIM AT A LATER DATE? One could make an argument that, being immortal, the Bulgasal do not have a need for brains in order to survive, but the human characters do not have such an excuse. If the show aimed for a sillier tone (e.g., Korean Odyssey) then this would be easier to overlook, but its mood is very firmly in the "serious drama" category, so that does not fly.
Maybe I am aging out of being able to enjoy fantasy shows, but this point is making me doubt if I can finish watching the show....
Just a few episodes to go....