She was played by Cindy Sampson.
Lisa and her son, Ben, were held captive by Crowley's henchmen in order to keep Dean off the trail while he and Castiel were searching for Purgatory. Dean manages to kill the demons and find Lisa and Ben, but when he grabs Ben, Lisa snatches him away and places a knife to his throat, and displays black eyes to reveal being possessed. Demon Lisa verbally taunts both Dean and Ben, stating that Lisa hates that Ben's in her life and even goes as far as to state a fallacy that Dean is his birth father. After Ben escapes the demon's clutches, Demon Lisa and Dean square off, with Dean beginning the processes of exorcising the demon out of Lisa. At that moment, the demon stabs herself in her own midsection, knowing Lisa will most likely die in her human state. Dean takes that chance and successfully exorcises the demon out of Lisa, who is later healed by Castiel.