Any film centered on demonology has an inherent responsibility for success: to make you, the jaded viewer, believe… or at least, to convince you to suspend your disbelief for just a few hours. Whether or not the film’s protagonist(s) are able to do so or not is dependent. In many, like director Scott Derrickson‘s own The Exorcism of Emily Rose, our main character is convinced of the Satanism at hand, desperately trying to get others to listen, while in others, like The Last Exorcism, our lead is one of the last to be convinced of the Devil’s works. Derrickson’s latest, Deliver Us From Evil, is one of the latter tales, in which our hero is slowly pushed to believe, bringing the audience along with him. Ralph Sarchie (played here by Eric Bana) in real-life is a retired NYPD detective, and it’s his memoir upon which this film is based. Bana’s Sarchie strides through his cases, forcefully and professionally, though the grim realities of mankind’s capabilities begin to take a draining and stressful toll on him. Luckily, his cop partner and comic-relief machine, Butler (Joel McHale), keeps him balanced. Sarchie’s neglecting his family life, wife Olivia Munn and daughter, thanks to an overbearing schedule at his poisonous job – and that’s before the demon stuff starts.