As I have read the novel the drama is based on, I was very eager to watch it.
I have to say, it is one of my favourite dramas!
Not only has it perfectly transferred the dark and mysterious scenery of the book onto the screen, but also have the actors done a beautiful job and the OST is remarkable.
As for the seemingly sad ending, I can only say one has to read the book to understand the hint given at the very end of the drama - or check the comments on Youtube or wherever the drama can be watched.
With only 36 episodes the drama can be considered relatively short for a chinese historical drama.
As the name suggests the drama is quite bloody and has a good deal of really evil characters, but what I like about the drama is the absence of a good character- bad character plot. All of the characters have reason for what they do and none of them is complety good nor completly bad.