During this period it was safe to say that he walked around without any real purpose in life and after a few years of this he broke down having found nothing to live for. Eventually, he did find a purpose in life when he switched from narcotics to homicide he began to gain a better appreciation of life, he is making the world a better place day by day by taking bad people off the streets and doing his fair share of good. He is great at detective work, we see this in all the interrogation scenes and even the moment he arrives on the first crime scene he's able to piece together everything, if you want a perfect visual metaphor from the first crime scene pay attention to how Marty looks down whereas Rust looks up. He has seen the very darkest that humanity has to offer and through working to take monsters off the streets he is able to do good. At one point his entire existence was darkness but after working he started to make it bright and through his work continues to every day. At first glance it may appear as though he eventually became broken again his messy hair, uneven moustache and drinking habit we see. When in conversation with the other detectives leads us to believe that he fell off the wagon but that isn't true. He may drink to drown out his pains but he stays focused he continues to look for answers until he's able to bring down the yellow king ultimately True Detective reveals to us how deep the problems facing this area of Louisiana go, we learn about corrupt politicians a self-serving state and how all of these are the root of the problem however there are also the roots of poverty, crime and violence. It's a problem that is institutionalised there are signs literally littering the landscape that bear the mark of the man they're looking for and doesn't stop at an individual level, instead it extends itself into every part of society.