Anatoly Onoprieneko, aka "Beast of Ukraine" was a 37-year-old when he confessed to killing over 52 people in the Ukraine.
His life began with some disruption and loss. His father was a well respected war veteran, but when his mother died when he was four, he was moved on to grandparents and eventually on to an orphanage. His father, however, kept his brother.
When he was arrested, he confessed to killing 52 people in six years from 1989 to 1995. First case was 10 family members; 2 adults and 8 children killed in a robbery he shared with an accomplice. Later, 5 people were killed in a car during a botched burglary. A family of 4 was shot down in a home invasion and the house burned down. Separate incidents occurred when he stopped cars and killed the drivers.
The majority of the cases involved killing an entire family in a fairly remote setting and then burning down their home. The family unit, it would seem, was a thing of disgust to this monster.
Amazingly, this voracious killer of entire families only got life in prison.