Serial killers have often some of the following in common
they are almost always males
many but not all come from a broken home and or from an abusive family background, often with a history of mental illness
many were institutionalized as a child at some point
more than half of all seral killers were bedwetters into their teens
usually have been drawn towards abnormal behavior since childhood such as sadism, violence, voyeurism, predation, arson
often have addictions and pretty much always
poor impulse control
many have attempted suicide repeatedly
many have an above-average IQ but lack discipline and often work menial jobs far below their potential or they enjoy jobs where they can exert authority
tend to be anti-social but many can be charming if it is to their advantage, some have successfully faked normal family life
may have a full back tattoo of the Red Dragon