Mainly because of KYJ. I've watched the 4 episodes. Wow! Every small detail in both the FL AND ML acting was so good. The expression and eye movement are wow. The plots are a bonus. Very well detailing. 

KYJ and then also contract relationship, cohabitation and fantasy. :)

 Peqa:

Call me vain but he's just hot. Haha. Well he's not the best actor and but there are some improvement in his drama, albeit small. There are many other talented actors like Lee Min Ki, who is not so visual but I'd watch his drama purely because of his acting. For My Demon, I like KYJ and I think she's a little bit talented than SK but both actors are visually appealing. The cinematography looks good too. Let see if the story become more interesting after this. 

I love Lee Min Ki! With him you can always bag on the fact that he will always bring his character to life! SK is hot but I droped his dramas before this! After 1 or 2 episodes even his visuals can't save him! He's making it interesting in this drama though! So I have hope for this one! Guess he's improving and I also think this character fits him like a surgical gloves! Hopefully he doesn't become a typo actor who can only act certain roles only. 

 Evie Zan:

I love Lee Min Ki! With him you can always bag on the fact that he will always bring his character to life! SK is hot but I droped his dramas before this! After 1 or 2 episodes even his visuals can't save him! He's making it interesting in this drama though! So I have hope for this one! Guess he's improving and I also think this character fits him like a surgical gloves! Hopefully he doesn't become a typo actor who can only act certain roles only. 

Song Kang face reminds me of Lee min ho , His face was also so heavenly type , his smile ,smirks but he was also an outstanding actor . I wish I could see him in again in such kind of legendary dramas - having best storyline , with beautiful actress , and so many costly vfxsss???Miss him so much after The king's eternal Monarch.

I just watched episode one after watching Sweet Home Season 02 whom I had high expectations but they made the second season too much slow to make season 03 and I wanted to stop my craving of waiting for this series so long so I watched my demon that got good result from the audience all over the world so I watched the first episode and got obsessed with it.

 Kaizoku:

I just watched episode one after watching Sweet Home Season 02 whom I had high expectations but they made the second season too much slow to make season 03 and I wanted to stop my craving of waiting for this series so long so I watched my demon that got good result from the audience all over the world so I watched the first episode and got obsessed with it.

So far I'm loving it too! 

Yoo Jungie and the trailers

Yoo Jungie and the trailers

The scene where Gu won jumped out of the window threw the middle finger at those gangsters lmao

Song kang is not a good actor, but his drama always had its hype, his drama always followed by critique about his acting. The hype is just to serious, 4% is not small number for drama these days. First episode was more than enough to fall on Song Kang's charm. Song Kang just too hot. No one can complain for his visual. He is just to perfect. I don't even care about the story line, All i can loving is Song Kang. Shit. 

 rismaartt:

Song kang is not a good actor, but his drama always had its hype, his drama always followed by critique about his acting. The hype is just to serious, 4% is not small number for drama these days. First episode was more than enough to fall on Song Kang's charm. Song Kang just too hot. No one can complain for his visual. He is just to perfect. I don't even care about the story line, All i can loving is Song Kang. Shit. 

Though he's very handsome he's not good at acting! Used to drop his dramas, watch maybe 1,2 episodes and then always dropped! Before I watch this drama, I was like gonna check out and then dropped it like usual! But much to my surprise he's good in this drama though! No doubt there's room for much improvement but guess he's starting to up his game! Really surprise that I enjoy watching him in this drama! So this will be my first ever SK drama that I'm not going to drop! Maybe his character is tailor made for him?? Hopefully he'll not turn into one of those actors who can play only one type of character! Wish he'll improve over time though because he's such a pleasure to look at! If he can combined with improved acting skills he may be much much more successful! 

If you notice , SK acting is more in the eyes , he can't I guess change his facial features according to the scenes , but his eyes  they act good . He definitely needs improvement and he will in near future.

 ThatElysiansoul:

If you notice , SK acting is more in the eyes , he can't I guess change his facial features according to the scenes , but his eyes  they act good . He definitely needs improvement and he will in near future.

Agreed that his eyes can convey emotions though he can't change his facial features! Hopefully he'll improve over time! Then it's a win for me since I enjoy watching dramas with handsome male leads and beautiful female leads! Bonus when leads are good at acting! 

The plot and genre. I just love a fantasy drama with a hint of history. 

Ps.: I saw a lot of people saying song kang's acting is not good. But I think he improved a lot. 

Yes his acting is not one of the best. But in my pov saying it's bad is a little wrong.