So basically both rainbow city and the serpent are experimenting on soldiers. Choi bitch face basically takes about those experiments and how Dr.oh's son (remember that one talking Adam guy at the beginning of the story"?) actually injected himself with the adam virus and the fake vaccine. The fake vaccine having been combined with malaria parasites (I don't think they revealed why so ima not say anything) because he believed in experimenting on humans. The four rivers of the garden of eden are the four founders, Dr.seok's mother, Wonho (which is the guy that got executed for being a rebel at the beginning, not dr.oh but the guy that invented the truth serum), and major kwak's parents. Wonho believed in dna alteration on infants and preformed inhuman experiments on ppl, and the serpent is his son. The son of Wonho and Dr.seok's mom making them half brothers.
Chapter 80 makes me feel like I'm taking an exam. What the hell is all of that info. Someone pls explain.