Evil prevailed at Saturday night’s world premiere of Ric Roman Waugh’s prison drama “Shot Caller” at the Los Angeles Film Festival at the Arclight in Culver City.

Actors on the red carpet recalled the intensity of the 2015 shoot, which centers on Nikolaj Coster-Waldau’s character being transformed from an upstanding family man working in finances to a prison gang leader named “Money.”

“I’ve never been as bad a guy as I was in this,” Jeffrey Donovan mused. “I have the keys to the yard. This was a dark dark dude that I’d never really done before. I put on 40 pounds. It wasn’t hard — I let myself be ugly. My wife was like that’s not a good look for you.”

Juan Pablo Raba, who played a leader for a drug cartel, had the same reaction. “Ric’s style is that he wants you to be ‘all in,’ like in the military, so he’d look me in the eye and would just say ‘Bring it,’ all the time. I gained 45 pounds of muscle, shaved my head and learned to walk differently.”

Raba had played a similar role in “Narcos” as Gustavo Gaviria, Pablo Escobar’s cousin, adding, “Even though the cousin was bad, he was also sort of a sweet guy, which I’m definitely not in ‘Shot Caller.'”

Jon Bernthal, who plays an ally of Coster-Waldau’s “Money,” noted that Waugh had researched prison life by working undercover as a parole officer. “I call Ric Roman Waugh a soldier of authenticity,” he added.

Waugh was particularly proud that scenes were shot in actual prisons, one that had been closed down. One of the key scenes involves 200 ex-cons staging a prison riot.

He also stressed that “Shot Caller” is a follow-up to his 2008 film “Felon,” in which Stephen Dorff played a convict who manages to make a better life for himself after prison.

“This movie is about what if these pieces don’t go back into place,” Waugh noted, adding that he’s hoping that “Shot Caller” will raise questions of how society should deal with its prison problem and the high rates of recidivism. “If you do the crime, you should do the time, but we also need to have more empathy for these people,” he added.

Coster-Waldau, best know for portraying the powerful knight Jamie Lannister on “Game of Thrones,” said the process of looking like a gang member was crucial and required several hours in makeup each day. “The makeup and the tattoos really helped get me into the character because it  transforms you, just like putting on a mask or a hat.”

During the post-screening Q&A, actors noted that shooting took only 24 days, requiring them to get into character quickly. Coster-Waldau elicited the biggest laugh of the night when he said, “When I hear about actors talk about their ‘process,’ I want to vomit.”

The film also stars Lake Bell as the wife of Coster-Waldau’s character, Omari Hardwick, Benjamin Bratt, Holt McCallany, and Emory Cohen. Production companies are Bold Films and Participant Media. Producers are Gary Michael Walters, Michel Litvak, Jonathan King, and Waugh.

“Shot Caller” will be aired exclusively on DirecTV starting on July 20, followed by a theatrical release Aug. 18.