And thus with a show so steeped in its own mythology, theories have spun forth uncontrollably about who the series villain, The Yellow King, truly is. Tons of theories have pinned Marty, Rust, Governor Tuttle, Reggie Ledoux, even the Lawnmower guy that keeps the grounds of the closed school. The problem with nailing down who exactly to suspect is that the show has departed from every facet of conventional story telling for a more grounded and realistic take on the occult. It would be easy to say that we haven't seen The Yellow King yet, but it would be like True Detective to say we actually already have.
Digging through theories I came across The Four Horsemen Theory. The basic idea behind it is that instead of just one main baddy, we may actually have five men involved in this deep conspiracy. Even for those with a keen eye for detail would probably have missed these signs but that's what makes True Detective so special. The clues have been right under our noses.
Again this isn't entirely my own, just a fan theory that I like and expanded upon.
This picture was in the house of Dora Lange's mother. Dora is obviously the woman found dead in episode one surrounded by all sorts of ritualistic and occult imagery. The picture depicts Dora surrounded by five horsemen literally. Could this be indication that the Five Horsemen are someone close to Dora or possibly that they have been around for a long time, killing and abusing women? The series certainly suggests this as Rust goes back through old files and finds numerous cases with the same spiral imagery on the victim's body.
This was found by Marty when he went into her daughter's room before dinner. The girls have enacted some sort of sexual scene with five men surrounding a nude woman. This certainly suggests that Marty could be involved with the Five Horsemen which is where his daughters would have gotten this notion from, or possible some sort of supernatural influence where the young susceptible girls are influences to play with their dolls in some sort of way just for Easter Egg implementation. Either way this is very disturbing and not something that a father would want to see his children doing, and not something that we as an audience should leave to coincidence.
The victims have often hinted at the man with the scars on his face being the Yellow King which describes someone we haven't seen yet. It could very well be the Yellow King at the top with his Five Horsemen to gather his victims. It certainly is plausible that there are many more people involved with this cult then we realize or could comprehend.
Only time will tell if this theory is correct as only two episodes are left in this amazing series. Marty says that the detective’s curse is not being able to able to see what’s right under their nose. I have a strong feeling that the answers we are desperately searching for are right in front of us.