With its basis in actual events, director Scott Derrickson’s Deliver Us From Evil required a certain amount of realism for its gritty tale of crime and demonic possession in New York City.

For Edgar Ramírez (Carlos, Wrath of the Titans), that meant trying to understand the mind of an exorcist for his portrayal of Mendoza, the renegade priest who draws skeptical Bronx cop Ralph Sarchie (Eric Bana) into a case involving evil spirits.

“I tried to research as much as I could, and of course always under the guidance of Scott Derrickson, our writer/director, who was very specific in letting us get out of control with this research,” Ramírez recently told a group of journalists. “These things can really get in your head if you don't have the right guidance. There's a lot of crazy stuff out there in these matters and it was important to keep us focused on what was really important, and what we would use in the movie. I read a book that Scott gave me, and I had interviews with real exorcists, but especially because I wanted to understand the psychology behind the title of exorcist.

“Being an exorcist or being a priest -- they're not characters by definition, they're activities,” continued the actor, who stars in the upcoming remake of Point Break. “So for me it was very important to understand their psychology and the reasons why they would become exorcists -- the reasons why they would devote their lives to helping people in that kind of situation, demonic possession, so to speak.”

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While Ramírez delved deeper into the world of exorcists, his co-star Joel McHale focused on other, more physically demanding areas. Not only did the Community star have to bulk up to look convincing as Sarchie’s tough police partner Butler, he had to learn how to wield dual knives.

“There was three and a half weeks of training every day,” he said. “It’s a Filipino knife-fighting style. They taught me as much as they could in that short period of time, and everything else was choreography. One of the greatest concerns of the movie was making sure everything looked real, it had to look real, I would be beside myself if it looked like shit. I really had to look like I knew what I was doing and that was my main concern. Now I can, if you would like me to, kill you with knives.”

Ramírez, who revealed last month that he’s “talking” with Derrickson about Marvel’s Doctor Strange, drew much of what he needed for his portrayal of Mendoza from the script, written by the director and Paul Harris Boardman (The Exorcism of Emily Rose).

“I was really drawn to the contradictions, the challenges and the struggles that this character has to go through and has to fight,” he said. “Normally in the stereotypical demonic-possession movie, you have the priest, this very one-dimensional character that knows all the answers. He knows all the prayers, and he talks about compassion and about forgiveness, but we thought really, has he been tested?”

“For me it was very important to see and to explore that this character knew about compassion and knew about forgiveness,” he continued, “because he himself had been through a process of self-forgiveness and self-compassion. So he could really talk about those important issues and important role that compassion, empathy and forgiveness, play in our daily lives, because he has been a recipient of that because he has understood what it means to be hopeless. What it means to feel helpless. I didn't want to play a character that just would have knowledge because he's a priest and he's supposed to know things. For me, it was important to see that he had gone through hell in order to understand it. He knew what he was talking about, because he knows what it is to make mistakes. He knows what it is to try and make amends. He can talk about sins and about redemption because he knows what it feels like to walk on the dark side, and that was very important to me.”

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However, Deliver Us From Evil isn’t completely enshrouded darkness; there are still elements of humor that shine through, courtesy of McHale.

“The gallows humor that cops have, or that paramedics have, or doctors have, I think is really funny and really interesting so that was very exciting to do,” he said. “I knew the jokes were really funny that Scott had written, I knew these were really funny jokes and I can tell a joke, but my main concerns were, you better look like a cop, you better look like you can fight with knives, and you better look like you were in the army. The rest of the time was spent making fun of Eric’s character and making sure things were buoyant and him and I fucking with each other is how I knew it was working.”

It may come as a surprise, but Ramírez has a journalism background, which he still taps into for his acting career.

“My aspiration was to explore human nature and try to understand the extent of the human condition,” he said. “As a journalist, I was also trying to do that, trying to understand and trying to answer certain questions that I was placing on myself every every day. As an actor now, I'm doing the same thing but probably from a more poetic point of view, but in the end, what I do through my characters and through the understanding of my characters, is to get to explore and also to understand the extent of the human experience.”

Deliver Us From Evil is in theaters now.