Viewed through the perspective of the Fencraft, Rust and Marty exist at opposing ends of the Realms. Marty Hart is a creature entirely of the Solar, a Solar so encompassing that it cannot be Solar-Lunar or Solar-Stellar, only Solar, as pressing as the gravity of the Sun itself. Meanwhile, Rust Cohle is one of the most Lunar-Stellar human characters I have ever seen in all fiction, but television in particular. Too often, characters meant to be Lunar-Stellar end up being not that at all, because the Lunar-Stellar is not a realm in which multiple seasons, or films, can survive in. But that is for later. For now, I will speak of the Solar.
The Solar pervades throughout TLBD. Through the Yellow King whom the cultists worship as equivalent to God, and the yellow color that indicates both His presence, and the presence of Earthly, but no less horrifying, power. Marty's hair is sunny blonde, and his home is soaked in that particular 1990's yellow. Yellow is the color of light -- but what that light means, what it brings with it, is an uncertain proposition.
There are many positives to the Solar, many valuable things, but TLBD digs deep into the horrors of the Solar, in all its annihilating glory.
I think that many popular portrayals in the Fencraft show the Solar world as a safe place, rather staid and boring at worst, like a dull-but-not-terrible-beyond-that hometown in spiritual form. The horrors under the Solar realm took place long ago, in raiding and war or who got to rule, but now? Now that's just sort of the way things are, and it is the job of the Solar-Lunar path to make them shake out right. But the purely Solar world is one where societal power makes all, sinks into everything around it, forces it into its patterns, because otherwise you are outside of the Solar world, and it's open season.
Marty starts out as the ostensible "straight man" of the story, seeming to be the saner of the two narrators -- but his narration is unreliable, and even in his first few scenes, we have seen what the cult of the Solar has wrought on him. The cult of the Solar is distinctive from the Yellow King cult, but is it, really? They are both about earthly power raised to the level of the spiritual, about keeping everyone in their place, damn the consequences for everyone who isn't lucky enough to be on top. Both are signaled, in TLBD, with the color yellow, through light and clothing and soap and food to seep back into everyone and everything.
At the start of TLBD, Marty has everything going for him. He's got a wife (they married at 19) and two girls, a nice house in the "right" neighborhood, and he gets along well with his coworkers. He played football in high school and in college, fishes regularly, keeps up with the "right" games, and basically has no reason to feel threatened in his life at all.
Marty is also one of the most insecure male characters I've seen in fiction, ever, and is my go-to example of toxic masculinity. I wrote the following earlier this year, and I stand by it.
Marty, by the time we meet him, both in the present day and in flashbacks, is a mess. He’s violent to the people he doesn’t care about, whiny to the ones he does, and damages every relationship he comes in contact with for not providing the proof (to him) that he’s a “real man”. He refuses to call his daughters by their names, only referring to them by pet names or insults, and has no pictures of them in his house (although there are his fishing trophies and several blown-up pictures of him in his college football outfit). He sleeps around because he thinks that it will prove to himself and to everyone else that he’s still young (he’s 32-ish at the time). Every man he meets, he first describes in terms of whether or not they could beat him up, or if he could beat them up.
By the end of TLBD, he’s learned to be a marginally better person, but it took being completely single and friendless for years, plus getting an axe to the chest. TLBD does not shy away from the fact that it was probably sheer laziness that kept Marty from being a serial killer, that Marty is bad and should feel bad.
Before I hurt Malcolm, we were talking about how Marty's loathing-and-horniness combo at anything female that enters his field of vision is palpable, and that he was probably thinking about moving into "Justified" Revenge On Conveniently Marginalized Women killings before he got partnered with Rust. Who, being antithetical to the Solar, is not the kind of person to let something go just because the dead person was "unimportant". But that's the exact sort of thing the cult of the Solar supports -- oh, there's some things you're just expected to go along with, you know, these things happen, boys will be boys.