By Anthony Breznican
Updated August 18, 2011 at 12:00 PM EDT

Sam Childers was a biker, a brawler, a drug dealer who sought redemption in Sudan, turning his bare-knuckle and bullet-slinging rage on warlords who were turning kids into child soldiers. Have a peek at this action-drama from director Marc Forster (Monster’s Ball, Quantum of Solace), out Sept. 23.

Childers is one of those rare characters who, if he was purely fictional, nobody would buy this story for a second. But he’s a real-life Rambo type, who still runs an orphanage/mission there — but he’s no angel. Screenwriter Jason Keller describes Childers as “reckless,” “wild-eyed,” and “always looking for trouble.” When Keller first met him with plans to adapt his story into a film, the lifelong tough-guy was characteristically hostile.

See below for how their first meeting nearly turned into a fight, and how Childers later dragged the screenwriter along on a few death-defying vigilante missions, and the one thing in the script that made the preacher’s temper flare …

“I met him for coffee, meeting him for first time in person around the middle of ’08 in Santa Monica,” Keller recalls. “He was absolutely quiet for our entire meeting, and glaring at me across the table. He’s a very intense guy. You can feel it. So I finished talking and he hadn’t said a word at all. I basically looked at him and said, ‘What do you think. And he said, ‘Look I don’t know who you are. I ain’t never heard of you and I don’t really care what you’re telling me.’ Basically, ‘I’m not going to trust you with my story because I don’t think it’s worthy of you.’”

Keller was taken aback by the brutal reaction. “I became very upset about it. I said ‘Look, Sam, I want to tell the story truthfully. Frankly you’re lucky I’m here listening to you and want to tell this story.’ I got up to leave, I felt disrespected. So I got up to storm off and he grabbed my arm and pulled me closer to him. ‘Relax … I was just testing you.’ He said, ‘I wanted to see if you’d piss your pants and you didn’t. Sit down, and let’s talk.’”

Eventually, they’d travel to the Sudan together, but before that Keller wanted to spend time with Childers and his family in their home outside of Pittsburgh. “I flew to Pennsylvania and lived with his family in his house. Hung out with them for a week.”

They didn’t hang out in church. “Basically, what we did was drive around to known drug dealers houses because the police had told him a dealer was selling bad drugs, and as a result kid in neighboring community had died,” Keller says. “He was always looking for trouble.”

It’s always tricky to write about a real-life figure. Maybe trickier than ever when that person is, let’s say, on the volatile side. This was a man who flew to a country torn apart by civil war and waged his own war against the people responsible for slaughtering so many innocents. Naturally, a writer wants to get the details right.

So Keller was worried when shooting was underway, and he began getting pushback from Childers and his family about the script.

“A couple of days into filming, I got all these frantic emails and phone calls, friends and family zeroing in,” he says. The source of their frustration? Not the violence or vengeance — the language. These native Pittsburghers did not like the apparent Southern twang Keller had given his character. “‘You wrote ‘y’all,'” Keller recalled them saying. “‘We don’t say ‘y’all’ we say ‘yinz.’”

Yinz can follow Anthony Breznican on Twitter: @Breznican.