The traditional portrait of mother and child suggested by the title receives a typically radical alteration in Korean auteur Kim ki-duk’s “Pieta.” One can certainly recognize religious overtones of redemption and forgiveness in the tale of a brutal gangster and the woman who appears suddenly in his life, claiming to be the mother who abandoned him at birth. But it would be a stretch to describe this as a spiritually uplifting story.

Kang-do (Lee Jung-jin) is the enforcer for a loan shark (Son Jong-hak) in a Seoul neighborhood filled with small workshops whose owners—machinists for the most part—are constantly in need of cash. His technique is to require the creditors to take out disability insurance, and if they fail to pay, maim them in industrial “accidents” and collect the funds from the policies. It seems a lucrative enough enterprise, but one that earns him the hatred of the clients he brutalizes without compunction, often in the presence of their wives, mothers or children. Kang do’s success is, however, contingent to a degree on his own lack of any emotional connections. He lives alone except for his pet snake, in a ramshackle flat that shows no sign of care or cleaning. If he had a family, threats against them might force him to mitigate his heartless methods.

That’s why his life gets complicated when a middle-aged woman named Min-sun (Cho Min-soo) shows up, following him around and even bringing him food. Finally in a tearful scene she admits to being his mother. His reaction is hardly to welcome her with open arms. Instead he beats and humiliates her sexually, until her acquiescence to every form of abuse gradually brings about a change that extends beyond his growing feelings for her to his treatment of his list of debtors. In a particularly effective scene, charged with high drama and some very dark humor, he actually lets a young man (Kwon se-in) off the hook when he expresses a willingness to be crippled because the money he borrowed was used to provide of his unborn child. The fellow even offers to give up two limbs rather than one in order to double the payout—if he can keep half for his family. Kang-do is so moved that he refuses to harm him.

But, of course, when former clients whose lives were ruined by his tactics learn that Kang-do has a mother, she becomes a target for them. After she’s nearly killed by one of her son’s victims (Jo Jae-ryong), he devotes himself more and more to her protection, but finds it difficult to keep her from harm. That’s the point at which “Pieta” takes a sharp twist that turns it into a grim revenge fantasy in which his old misdeeds come back to haunt him and demand satisfaction, even as he goes about obsessively searching for the men he crippled and finding them either mere shadows of their former selves—or underground.

Kim and cinematographer Jo Yeong-jik provide gritty, desolate settings for this lurid but undeniably powerful story, and the lead performances are compelling, even if they both go to histrionic extremes in a few scenes—a common reality in Korean melodrama. The secondary roles are well filled, with Kwon Se-in making an especially vivid impression.

Though “Pieta” is a violent film, Kim keeps the explicit mayhem to a minimum, especially by the standards of many younger Korean directors. Still, it may prove too heady a brew for some viewers. If you can endure its uncompromisingly bleak perspective on the human condition, however, you should find it a strong addition to Kim’s extensive filmography.