The entire series is written by Lee Soo Yeon who was inspired by the Korean adage "We cannot rule those who want nothing" to create the character of Shi Mok.
Season 1 plot is inspired by the corruption scandals around Samsung Group and its owners (Lee family) and by the 'Busan case' when during many years hundreds of prosecutors were 'sponsored' with gifts, parties, and free prostitutes in exchange for commercial benefits.
Unlike usual South Korean dramas, the series was developed as a potential multi-seasonal program, with most of the filming have already been pre-produced prior to its broadcast. The 3rd season hasn't been commissioned yet by tvN.
The drama was featured on New York Times list of 10 Best TV Shows of 2017.
Note on Korean currency: One US dollar is very roughly equal to 1,000 South Korean won. Thus, a business deal involving 700 billion won is roughly equivalent to a 700 million dollar deal.