Karma.

Governor Heo, worried over the plague that's sweeping the country, rebukes the Kus who make amulets to ward off evil. Heo castrates the husband when he makes superstitious claims and takes the wife as his mistress. Heo continues to be tormented by hallucinations and nightmares and begins to blame it on the Kus' curse. He kills the couple at their reunion and unable to ward off his bad karma, dies from leprosy.