In chapter 3, Marty forces his way inside his ex-lover's house, physically assaults and threatens her date, screaming and pointing incapacitating spray at his face while she shouts at him to stop and leave.
A father is tortured/murdered by an adult son. The same man also has a questionably consentual incestuous dynamic with uis intellectually impaired female direct relative. It appears to have been a lifelong familial abuse cycle for her, going back as far as her grandfather.
Interpretively; the entire season focuses on a collective of politically privileged, caucasian men, orchestrating a three decade long sprawling cover up for dozens of abductions, rapes, torture, possible sacrifically motivated murder and serial killing of socially vulnerable children and women. A routine "chain of command" system, from the state governor down, is instituted for serveral generations; making it an untouchable family tree.
The very first scene... A heard of elk jump to their death but it does not show them dying.
The first time you see Rose, she is cutting open a wolf and it's very graphic.
In the last couple episodes, dogs are threatened with physical abuse and murdered. In S1:E8 @ 0:04:45 - 0:05:05 a (cast iron?) object is thrown at a German Shepherd, possibly injuring it causing it to make a distressed yelp in fear. In the final episode S1:E8 @ 0:28:15 a dog is verbally abused on an off until 0:29:15. When it gets loose, it makes a terrible cry in pain (S1:E8 @ 0:29:25 off camera). At S1:E2 @0:29:48 the camera pans past the bloodied body of the animal for about 4 seconds; the body is shown at a distance/partially obscured again 0:32:57
The last episode of season one (form & void) is pretty messed up & graphic. There are several shots that imply animal abuse. Dogs and cats. Very graphic. If you have to watch it skip minutes 28-37
Several victims are found to have drugs in their system, and one abuse survivor describes the feeling of being drugged, but it's not shown or simulated onscreen (excluding characters who use drugs voluntarily)
there is a video tape presented in the show of a young child being raped. there is a cut scene before anything graphic is shown, but it is clear what has happened and could be triggering to some.
Reference in chapter 3 of someone being castrated with a razor in jail, description in chapter 4 of a similar (lengthier explanation) torture and murder method used by a drug cartel involving cutting.
Several characters are unlawfully beaten by police officers throughout season 1. Rust at one point describes a nasty cartel torture method, but it isn't shown.
Rust visits a young woman who he rescued from abuse as a child. She is now in a psychiatric hospital and when he mentions the facial appearance of someone who he believes abused her, she has a panic attack and cannot stop screaming. She defintely has PTSD from her trauma
other comment is not true, the killer does not have d.i.d., he does put on different accents and is mentally ill, but is not implied to have d.i.d. at all
Mental illness is implied in two characters. The focus character has features of some altered personality disorders. A female character very obviously has a form of unspecified intellectual disability, potentially autistim and congenital disorders, which aids in her groomed exploitation and complete social isolation.
An inmate slits his wrists in his cell off-screen. you see the aftermath. A detective also tells a woman who murdered her children that she should kill herself in jail.
If harm to babies is a trigger: around 47 minutes in, Marty tells a story about a baby dying in a horrible way. We see the crime scene of the baby's death, and while the body itself is out of focus, there is blood and the scene is disturbing.
Near the beginning of the episode, there are a few short sexual scenes (no nudity) between a character and what's later described as "at least a half-sister"
Several times in season 1, Rust either discusses or monologs about the meaning of life and existence, or what happens after death. There is a nihilistic bent to it.
Episode 1: A tongue is found (when the delivery man drops his phone) and there are closeups of it when the detectives look into it.
There is a flashback scene from Navarro as a soldier and there is a woman with half of her head missing.