i have known 2 children who seemed to be 'devil spawn' at very young ages. one was 6 the other 9, when i knew them.
the 6 year old was so mean and cruel/sadistic, if teachers hadnt seen it themselves, nobody would have believed it. he took a toy truck and beat a little girl unconcious in the playground for no apparent reason. she still has visible scars 25 years later. he moved away, so i have no idea whatever happened to him, but i know he was not seriously punished for what he did.
the 9 year old was apparently sexually precocious. he raped one of my cousins during a sleepover. she was 7. it was a real rape, he choked her till she was helpless. he went to juvie for it, he later went to prison for another rape. still in angola as far as i know.
neither of these children had troubles at home, kids usually sense it if other kids are abused. both had good families. the 9 year old is family sorta.
i like to think all children are good, but i know they arent, sadly.