Catholic corruption and sex abuse allegations have made global headlines for years. Now a new film shines a spotlight on scandals at South Korea's vast and politically powerful Protestant churches.
South Koreans are enthusiastic religious believers, with 44 percent practising or considering themselves religious, according to state data. Protestants are the largest group, followed by Buddhists and Catholics.
The country is home to several of the world's biggest "megachurches", with hundreds of thousands of members, while conservative evangelical church groups boast millions of followers and enormous political lobbying power.
Many star pastors build enormous personal fortunes and often pass control over their churches to their own children in a generational power transfer.
But corruption or sex scandals involving evangelical leaders make frequent headlines, as do court battles over lucrative congregations.
The plot of "Romans 8:37", which had its premiere at the current Busan International Film Festival in South Korea, centres on the struggle between two powerful pastors for control of a fictional evangelical church, along with its vast wealth and political influence.
Charismatic young preacher Joseph Kang accuses his aged, conservative predecessor Reverend Park of embezzling millions of dollars from church coffers to bribe politicians.
But Kang soon becomes a target of personal attacks by Park's followers, who accuse him of fraud and other crimes during services to try to force his resignation.
Each side sets up teams to discredit their opponent and sway public opinion via the media, with no tactic left untried, including mutual allegations of embezzlement, bribery, faked credentials, sexual abuse, even heresy.
But few question the integrity of the church as the mud fight rages.
Kang's campaign eventually suffers a major blow after female followers accuse him of sexual abuse, and congregation elders decide to keep the scandal under wraps "for the sake of the church".
The plot is loosely based on true stories involving South Korean churches, says director Shin Yeon-Shick, himself a lifelong Christian.
"Personally this was such a painful movie to make," he said. "I felt really heavy at heart.
"Some church members have expressed discomfort at this film, but I think we need to confront this reality and the pain we deserve to suffer for being part of this system," he told AFP, criticising what he called a "cartel" of churches in the country and a culture of impunity.
In one high-profile real world case, a founder of the Yoido Full Gospel Church -- a Seoul megachurch with more than 500,000 followers -- was convicted this year for forcing the church to buy company shares from him at inflated prices, causing it to incur losses of $13 million.
Some South Koreans mock religious leaders as "managers of Jesus, Inc", and Shin said many churches in the country do not promote the self-reflection and introspection essential for spiritual growth.
To his mind the issue is also deeply rooted in South Korea's culture of collectivism, which Shin said meant "people are rarely given a chance to think individually and independently, or to express their own opinion".
"So they want to belong to whatever is the biggest and most powerful to feel safe -- whether it's a megachurch or a big company," he added, "and try to ignore the suffering of individuals in the name of protecting the establishment".
The film takes its title from a Biblical passage in which St Paul addresses the issues of sin and salvation through Jesus.
"One should be on God's side," Pastor Kang's father says at one point. His son, he adds, "thought God was on his side".