Taoba Yu was just brilliant as a villain, such a wonderful well written character! I was always on my toes (and we all know how great that would be as a lover lol). I can accept his terribleness and it does show the darker side of loving someone that you want to blackmail them (very terrifying and not healthy of course). The actor who played him was so marvelous, I hope he got awards for that role.
https://www.dramacool9.co/long-time-no-see-2017/ (says 3 episodes but all 5 are in there, they're just compacted in)