Oola Blint AKA "The Angel of Mercy" was a villain in the 2000 AD comic strip Judge Dredd. She was a serial killer whose actions seemingly were motivated by her belief that she was freeing people from the chaos of Mega-City One, but in reality, she only just enjoyed killing people and preferred to kill them when their not volunteering for death. She killed people by incapacitating her victims before giving them a lethal injection
Oola Blint was a seemingly kind-hearted and pleasant resident of Mega-City One, but over a period of several years, along with her weak-willed husband Homer Blint, she went a killing spree and when her husband discovered what she was doing, she convinced him that her actions were mercy killing Mega-City One citizens, which he was convinced. Oola managed to evade detection for several years by the Justice Department until her crimes were traced back to her by Judge Dredd. Unfortunately, she and her husband escaped from Mega-City One to Brit-Cit where their, they opened a legitimately legal euthanasia clinic, but Oola found out she didn't get any pleasure in killing willing victims and went on another murderous spree. Her husband Homer discovered this and reported this to the Judges, so she gave him a lethal injection which almost killed him, but he was saved by Judge Dredd (who was investigating the murders) and Oola gave herself up without a fight. Both Oola and Homer were returned to Mega-City One and were sentenced to life imprisonment for their crimes. They were placed in adjoining cubes but Oola refused to talk to her husband due to him informing on her. Several years later, an author names Amis Barnes tried to interview Oola about Judge Dredd, but she threatened to kill him, having started to go more and more insane since her capture.
Outwardly, Oola Blint seemed like a friendly and easy-going person who believed she was putting people out of their misery from the chaos of Mega-City One, but in reality, she was a psychopath and only killed because she enjoyed it.