Well, the Josef Fritzl story is about a man who committed heinous crimes. He locked his own daughter in a hidden cellar in their house for over two decades. He treated her horribly, abusing her in many ways including sexually. The discovery of this situation was a huge shock. It showed how one person can carry out such atrocious acts in secrecy for such a long time, and it also raised questions about how such a situation could go unnoticed for so long.
Mengele was interested in studying genetics and heredity in the most grotesque ways. He carried out experiments like injecting chemicals into the eyes of twins to try and change their eye color. Many of his subjects died agonizing deaths as a result of his procedures. His actions were a part of the larger horror of the Holocaust, where the Nazis aimed to exterminate Jews and other groups, and Mengele's experiments added to the brutality and inhumanity of that dark time.
The story became known when a child's medical situation arose. Josef Fritzl took the ill child to the hospital. The medical staff noticed some strange aspects in Fritzl's account of the situation. Their concerns were strong enough to call in the police. As the police started to look into it, they found more and more evidence that something was terribly wrong. Eventually, they discovered the underground prison where Elisabeth was held and the awful truth about her long - term abuse by her father.
A common theme is mystery. Since Josef's character often has an air of mystery, and the addition of the moonlight setting in the fanfiction, it creates an overall mysterious atmosphere. For example, the oc might be trying to figure out Josef's secrets.
I don't know without more information about the story. But usually, the main antagonist could be someone who poses a significant threat or obstacle to Josef's goals or well-being. It could be a person with opposing interests or a force that creates difficulties for him.
It depends on your region. Sometimes, it could be available on cable TV channels that focus on true crime documentaries. You could also look on specialized documentary streaming services.