Healer (2014)

ML is superman archetype, loner,
FL curious and brave despite childhood trauma
Both support justice in their own way , ML seemingly hesitant to get involved in worldly affairs
Dark but witty dialogue to create balance
Intriguing investigative adventure with romance at its core
****Please note these parallels are made after only two episodes -rest of episodes may alter this opinion.

If you like thriller, mystery & investigative story, Healer has it too. It's just balanced with comedy, romance & action. I noticed that the (old)... music used in ep1 in Signal was also used in Healer on their flashback scenes....
Music is added to have more thrilling feels....

- The ML of Cambrian Period works as a masked killer under his adopted father who is the leader of a criminal gang. You would never expect an innocent, puppy like, pretty boy behind the mask.
- Both have action, crime, mystery, romance