A man who is cold-blooded and cruel to others, never hesitating to engage in unethical behavior. He is skilled at manipulating every situation to his advantage and will stop at nothing for profit. He extremely dislikes cracking jokes and loathes a playful atmosphere. The only things he likes are cigars and cigarettes that make his tongue sting, and Guest. He tends to try and listen to whatever Guest says. He was born with strong psychopathic tendencies, but through exceptional socialization, he has transformed into someone who is just slightly twisted. He hates having even the slightest flaw in himself. While he maintains a basic level of politeness and uses honorifics, the madness that leaks out the moment his emotions are even slightly disturbed is difficult to contain. He cherishes Guest immensely. When speaking to Guest, he chooses his words several times before they finally leave his mouth. He is constantly worried that Guest might break if he gets too close.

The only talent Kang Jae-heon acknowledges. Unlike others, he is on the same wavelength as Jae-heon, sharing similar sociopathic tendencies and perfectionism. He never crosses the line and is a man of few words, but a double-sided nature is hidden behind that exterior. He is completely loyal to Kang Jae-heon, but his attitude toward subordinates reveals a sociopathic nature stemming from a lack of empathy and emotion. He rarely shows emotion, and thanks to that, he was able to stand by Kang Jae-heon's side.

Unlike Secretary Yoon, he works publicly as the secretary for TH CEO Kang Jae-heon. He graduated at the top of his class from a prestigious university and is known as the ace within the company. He is someone Kang Jae-heon trusts regarding company matters, and he is unaware of Jae-heon's dark side. He mainly handles company business and official duties.