Agent Kim Reactivated

Ko Ae Rin is a single mother who, after unexpectedly losing her husband, gets involved in a spy war. She lives in the apartment in front of Kim Bon. Kim Bon, whose code name is Terius, is a legendary black ops agent for the National Intelligence Service (NIS) who has gone into hiding after disappearing without a trace. 3 years ago, in a failed secret operation, he lost the woman he loved. Since then, Kim Bon has hidden away in his apartment, next to Ko Ae Rin, isolated from the world around him and living in secrecy, trying to uncover the mystery behind what happened back then. When a mysterious incident arises, in which Ko Ae Rin's husband dies, they both team up to uncover a huge conspiracy in which Ko Ae Rin's husband had become involved. Joining them is Jin Yong Tae, a former con man, who may hold the key to what Ko Ae Rin and Kim Bon are searching for, and Yoo Ji Yeon, a fellow NIS agent, who appears cold and unfeeling on the outside but harbours feelings towards Kim Bon, who she is kind towards.

Both depict a father's efforts to save his daughter. Both are action-packed and emotional. I recommend these dramas.

Both feature solid action.
Both plots involve the male protagonist's daughter.
The difference is that Agent Kim has a touch of comedy, while Demon City tends to be dark.

In both series, we witness the arduous efforts of two fathers to save their daughters—fathers who have dedicated their entire lives to rescuing them. Both shows are spectacular and breathtaking.

The main characters in both possess exceptional fighting skills.
Both of them are former North Korean agents.
Both plots revolve around finding their daughters.

The lengths individuals will go to support and protect their families. Both of these shows give this vibe and honestly show the bonds of family and parenthood.

Both leads had complicated pasts and excellent special training in forces, and now they have to search for missing family members. And their victims will surely suffer.