Due to the numerous twists and turns, all spoilers are unmarked.
Dock O'Kelly a.k.a. Father Daniel Flynn
An aging criminal masquerading as a priest.
- Complexity Addiction: His plan to masquerade as a priest to avoid drawing attention is needlessly complicated and ends up causing the exact opposite effect than intended.
- Cool Old Guy: According to his flashback, he frequently got into fights with gangs while in prison, and gave better than he got. When given the chance, he does the same to the much younger Billy Lee.
- Even Evil Has Standards: He may be a career criminal, but he was incensed when it looked like his associates might've killed the armored car crew and in the present day he is thoroughly disgusted by Billy Lee.
- He also tries to drug Darlene specifically so he doesn't have to hurt her to get access to her room.
- Laser-Guided Karma: His attempt to drug Darlene and get access to her room ends with a bottle getting smashed against his head. While talking to her later, even he admits he had it coming.
- Let Them Die Happy: Despite being outed as a fake priest, he plays the part to take Miles's dying confession.
- Scatterbrained Senior: Is suffering from dementia or Alzheimer's, which caused him to forget which room his brother buried the money from their last big score in.
- Sinister Minister: Subverted, when he drugs Darlene it seems like he'll turn out to be a creep, but he's actually neither truly sinister nor truly a minister.
- Would Hit a Girl: Would shoot a girl, when Rose stabs Miles.
- Played straight however in his attempt to drug Darlene so he doesn't have to hurt her to gain access to her room.
- Your Days Are Numbered: He's old and suffering from advanced dementia, so it won't be long before his time is up. His main goal is to retrieve the buried money, and live out the rest of his days in peace.
A struggling singer.
- Action Survivor: The only person at the hotel who is exactly who she claims to be and has no ulterior motives for being there; she nonetheless manages to survive and even fight back.
- The Cynic: Her past with the music industry has left her jaded and cynical.
- Horrible Judge of Character: Inverted. She has an excellent sense of when someone is just completely full of it.
- Screw This, I'm Out of Here!: Attempts to flee after Flynn's failed attempt to drug her, but is forced to stay because the cars are all sabotaged.
- Sole Survivor: A weird example. She's not this at the end of the film, as Flynn also made it out alive, but it's been made clear that he doesn't have that much time left, meaning she presumably becomes this shortly after the ending.
A Southern criminal.
- Abusive Parents: Apparently took the brunt of her father's physical abuse to protect Rose.
- Big Sister Instinct: Everything Emily does in the movie is to protect Rose. She took most of the abuse from their drunken father for her and tries to save her from the manipulations of Billy.
- Cop Killer: She blasts a FBI agent with a shotgun.
- Jerkass: Her first scene has her bluntly asking for a room, ignoring everyone around her, and signing the register with "FUCK YOU".
- "Shaggy Dog" Story: Everything she does is to get herself and her sister Rose away from Billy Lee and his cult. Not only does she fail, she's killed and her sister dies shortly after.
Agent Dwight Broadbeck a.k.a. Seymour Laramie Sullivan
An FBI agent masquerading as a vacuum cleaner salesman.
- Decoy Protagonist: Followed closely at the start of the film, but doesn't get much attention after he's killed by Emily.
- Destroy the Evidence: He's been sent to the El Royale to get rid of the FBI's surveillance equipment.
- Good All Along: Initially he comes across as a sleazy salesman with a racist streak, but privately he's revealed to be a dedicated family man with a strong sense of justice.
- Jerkass: He initially appeared to be sleazy and racist salesman but it is subverted. It was just a front when in reality he is an upstanding FBI agent.
- Killed Mid-Sentence: Emily cuts him down with a shotgun blast as he tries to explain his actions.
- No Good Deed Goes Unpunished: He disobeys direct orders to save a young girl who appears to have been kidnapped, but is mercilessly killed as a result.
- Not Quite the Right Thing:
- While waiting for the bellhop, he makes coffee and insists that Darlene have a cup, though she doesn't really want to. Remember, he's white (and ostensibly from the south), she's black, and racially segregating restaurants and hotels had just been banned in 1964 (which some Southerners were still pretty pissed about). Taking that into consideration, him making coffee for everyone and serving her out of the same pot and set of cups is a clear way of saying "I'm not one of those segregationist southerners that would be angry you could stay in the same hotel as me, and you don't have anything to worry about from me (especially as a woman alone)." However, when the bellhop comes up, she's told she has to pay for the coffee - coffee she didn't want, when she's clearly trying to pinch pennies - and Sullivan doesn't notice. So. Good intentions, nice gesture, bad execution.
- The kidnapping he tried to interfere with turns to have been an attempt by a young woman and her brainwashed sister to escape from a dangerous cult. Not only does he get killed for his trouble, but the girl he was trying to rescue phones the leader of the cult in question and brings him to the hotel, which leads to the deaths of a whole bunch of other people, herself and her sister included. Broadbeck really should've listened to Hoover and stayed out of it.
- Traveling Salesman: Broadbeck's cover as Seymour Sullivan.
- Would Hit a Girl: He knocks Emily down when he's trying to rescue Rose from her "kidnapping." He pulls his punch though, and she gets right back up and shoots him without having a mark on her.
Emily's impressionable younger sister, a cult member.
- Ambiguous Situation: It's unknown if she was deep down Evil All Along even before joining the cult or irreversibly Brainwashed and Crazy courtesy of Billy Lee.
- Berserk Button: Don't get between her and Billy Lee. She will punch your lights out or stab you to death if you do.
- Big "NO!": When Miles kills Billy Lee.
- Cain and Abel: The Cain to Emily's Abel.
- Cute and Psycho: She is an adorable, waif-like young woman with a child-like demeanor. She will also beat you to a pulp or gut you like a fish at Billy Lee's slightest indication.
- Defiant to the End: Stabs Miles just before Flynn guns her down.
- Emotionless Girl: Rose doesn't appear to react much to the things that happen to her, showing little struggle against her kidnapping by Emily and treating Emily's murder of Sullivan as a slight curiosity. She even shows no emotion to Emily getting murdered by Billy. The only time she does show emotion is when Billy is killed by Miles and she fatally stabs him in revenge.
- Even Evil Has Loved Ones: Subverted with Emily as she largely ignores her help and barely reacts when Billy kills her, but played straight with Billy who she'll do anything for.
- Knife Nut: Her apparent weapon of choice is a hunting knife, as she uses one both times that she kills: first the man in Malibu and then Miles during the movies climax.
- Tragic Villain: Rose, while obviously very screwed in the head, was forced down the criminal path by Billy and was pretty much brainwashed by him into becoming who she became.
A young concierge at the hotel.
- Alliterative Name: Miles Miller
- Almighty Janitor: Turns out the meek, nervous receptionist is a veritable killing machine once he gets his hands on a gun.
- Cold Sniper: Used to be one, though by the time of the film, his trauma has caught up with him, leaving him a nervous wreck. The film's climax sees him slip back into this mold, with devastating results.
- Crouching Moron, Hidden Badass: Miles is first depicted as an incompetent junkie, then as a nervous pawn in "management's" blackmail scheme. It isn't until the final act that his past as a natural-born sniper who killed 123 men in Vietnam is revealed, and he uses those skills to take out Billy Lee's gang.
- Deathbed Confession: Even though he knows Flynn is a fake priest by that point, he confesses his sins before passing away.
- Death Seeker: Certainly has shades of this, given his past. Notably whenever he's held hostage by another character, Miles' seems less concerned for his life than for his soul.
- One-Man Army: Put a gun in his hands and he will kill anyone in his way, as proven when he guns down half a dozen members of Billy's cult in under a minute.
- Shell-Shocked Veteran: Is wracked with guilt over the many people he killed as a soldier, as well as the fact that he apparently enjoyed the killing, and that he was the only survivor of his unit in one engagement.
- Two-Faced: When Emily shoots Sullivan, the shot goes through the window Miles is behind and several pieces embed themselves in the left side of his face.
- Would Hit a Girl: If they're one of Billy Lee's cultists, yeah, he'd hit them. With bullets.
A charismatic cult leader.
- Affectionate Nickname: Subverted. He tends to refer to Rose as "Boots" due her footwear, but it isn't sincerely affecionate. It's just another method of control and brainwashing.
- Beard of Evil: It goes along with his Charles Manson vibe.
- Big Bad: He's a violent killer who swoops in and forces the remaining characters to join forces against him.
- Boom, Headshot!: How Miles takes him out.
- Conflict Killer: All the tension and conflict in the El Royale between the numerous guests has to be put on hold when Billy Lee turns up.
- Does Not Like Shoes: He's never shown wearing footwear in any of his scenes.
- Ephebophile: It's heavily implied just short of outright stating it that he's in a sexual relationship with the underage Rose, and probably has a similar arrangement with the other young girls in his cult.
- Faux Affably Evil: As befitting a cult leader, he's a charismatic speaker who quickly gains the confidence of others. In truth, he's a psychotic egotist who sadistically pits his followers against one another.
- Hate Sink: While all other characters have at least some redeeming qualities, Billy Lee is utterly devoid of them.
- Hunk: He's muscular and physically very attractive, a fact he uses to lure young women into his cult. Being played by Chris Hemsworth makes this a given.
- Killed Mid-Sentence: Miles blows his brains out just as he's somewhat nervously trying to talk him down.
- Large Ham: He loves, loves, loves to hear himself talk.
- No Historical Figures Were Harmed: He's heavily, heavily based on Charles Manson.
- Paper Tiger: While he's big and muscular, and loves to play up his image as an invincible cult-leader, he's not much in a fight, as Flynn overpowers him despite being smaller and several decades older, and of course, he's no match for Miles simply shooting him in the face.
- "The Reason You Suck" Speech: Gets one from Darlene, who calls him out as just another petty little man who takes advantage of those weaker than him.
- Smug Snake: Darlene, who's seen his type before, correctly identifies him as just a smarmy douche who's only interested in power and having sex with his female followers. Her assessment actually manages to shut him up for a few minutes.
- The Sociopath: He's very charismatic and charming, when he needs to be.
- Southern-Fried Genius: He likes to play up his Southern roots, and whatever moral failings he may have, he is extremely cunning and smart enough to have an entire cult worth of people wrapped around his little finger.
- Walking Shirtless Scene: Constantly struts around with his shirt open, when he wears one at all.