Song Hye-kyo (right) and Jeon Yeo-been anchor the film as Sisters Unia and Michaela. Photos: Handout

The shadow of The Exorcist (1973) haunts every occult film daring to tread the path of demonic possession.

The Priests 2: Dark Nuns takes on that spectre by shifting the lens to territory rarely explored – the world of nuns wrestling with dark forces beyond the church's sanctions.

This spin-off of the 2015 Korean hit The Priests pivots from its predecessor by bringing two women to the fore. Where the original played like a supernatural crime caper, Dark Nuns delves into the bond between sisters of the cloth who risk everything in a forbidden ritual.

Relative newcomer Kwon Hyuk-jae steps into a franchise that proved a launching pad for Jang Jae-hyun, who went on to direct occult blockbusters Svaha: The Sixth Finger (2019) and the award-winning Exhuma (2024).

Song Hye-kyo and Jeon Yeo-been anchor the film as Sisters Unia and Michaela.

Wild-eyed courage meets measured doubt – Song's Unia is all grit and nerve, while Jeon plays the more contemplative Michaela.

Their chemistry spilled off-screen at a press event, where the stars seemed as bonded as their on-screen counterparts.

"She's my messiah," Song said, gesturing to Jeon with a laugh.

It's Song's first Korean film in 11 years, and her first brush with the occult genre.

Fresh off her turn as an ice-cold avenger in Netflix's The Glory, she credited Jeon for helping her navigate the demands of intense exorcism scenes.

"We couldn't do it without each other," Song said.

The sentiment flows both ways.

Jeon, who had long admired Song from afar, found strength in her co-star's presence.

"What drove me forward was Song's eyes," Jeon said.

She took to calling Song "Dear Unia" between takes, a term she reserves "only for those truly special to me."

Teen actor Moon Woo-jin captures the cast's collective praise for his portrayal of the possessed boy in the film.Their off-screen bond seemed to mirror their characters' journey -- two women united against forces, both supernatural and institutional, to save a young boy's life.

The film rounds out its cast with Lee Jin-wook as a priest and psychiatrist who denies the existence of demons and instead insists on medical treatment.

But it's 15-year-old Moon Woo-jin who captured the cast's collective praise for his portrayal of the possessed boy at the story's heart, delivering what the director calls a "mesmerising" performance.

A surprise breakout hit, the original Priests drew 5.44 million viewers to theatres in South Korea, outpacing James Bond's Spectre at the box office. – The Korea Herald/Asia News Network

Dark Nuns is showing at cinemas nationwide.