O Guardião da Noite (2014)

Both stories based on the ghosts and dark magic. If you love stories of ghosts and dark magic you'll love them both. :) :)

Both dramas has a main character who can see ghosts but pretends he doesn't. Both dramas takes place during Joseon dynasty as well. Both dramas gave similar feel to me to the point I one night had a dream where I mixed up both of the dramas and woke up thinking "what drama was that? I need to watch it" :D

Both have a supernatural and historical element to them. Both have a special prince who struggles to become king while fighting demons/spirits. Both have a tribe girl who helps him (who also has an older sister) and who he eventually falls for. Both also have an evil priest/shaman and some sidekicks to complete the love polygon.

Both have shamans, dark magic, and evil, as well as a royal lead under some sort of a curse. Both dramas have a similar vibe.

Both are historical dramas and center around cursed princes that become driven to punish evil in their kingdoms. NWJ has supernatural and fantasy elements

Both are coming of age stories in which young men have to mature and take hold of power and responsibility that is both difficult, meaningful and have personal stakes.

Both are coming of age stories in which young men have to mature and take hold of power and responsibility that is both difficult, meaningful and have personal stakes.

The Moon that Embraces the Sun is also a historical drama just like Night's Watchman. They both have fantasy as their main genre.
They also involve Shamans. The main lead actress are both shamans.
The main actor in both dramas is a royal. In TMTETS he is a king, while he is a prince in the Night's Watchman.

Now that I think about it Il Woo act in both but in the MTETS, he is the older prince, in NW he is the younger prince.
I just kept being reminded of TMTETS while watching this drama =D

The kings in both dramas are almost or completely (you be the judge) insane.