Why am I obsessed with morbidity?

Ever since I was about 13 I've been obsessed with Adolf Hitler, I'm 15 now and still am. The only things that interest me are people like Jack the Ripper, The Zodiac Killer, Jeffrey Dahmer, etc. I'm also interested in other things like black magic and I enjoy the dark and dark places, I plan on moving somewhere cold and dark when I'm older. One of my more recent person of interest is the doctor at Auschwitz who's name was Dr. Josef Mengele who performed experiments on people. Many times without any use of anesthesia. However mainly what I'm asking is why am i interested in these things to the point of obsession?