I was born with the devil in me,' [Holmes] wrote. 'I could not help the fact that I was a murderer, no more than the poet can help the inspiration to sing.
Killing is killing whether done for duty, profit or fun.
Maybe this is why so many serial killers work in pairs. It's nice not to feel alone in a world full of victims or enemies. It's no wonder Waltraud Wagner, the Austrian Angel of Death, convinced her friends to kill with her. It just seems natural. You and me against the world.
Kill one and you might as well kill 21.