Doctor Mengele is such a powerful character historically, as powerful as Nazism itself, so these subjects always tend to be the protagonists. What I think is that despite this historical references, Wakolda or The German Doctor is a very intimate story.

When I wrote Wakolda at first I wasn't conscious that I was writing about something so close to or that had so many similar elements with XXY. It was just after I was done writing that I noticed it. I think both teenagers in each film have many similarities, and Mengele is the extreme version of the plastic surgeon in XXY. Both stories definitely have several ideas connecting them.

In the case of my second film The Fish Child (El Niño Pez), I had written the novel about 5 years before I made into a film. In the case of The German Doctor I had published the novel a year before I started writing the script, I even had another project to shoot. But I had this idea of the powerful cinematic language from the novel that I couldn't let go of.

The Mapuche are our indigenous people from the south, the Patagonia. They are a vey wise and luminous ancient cavitation, which is completely opposite to where Nazism was headed. In the novel [Wakolda], the theme of racial purity and the Nazi obsession with it was much more developed.

When I started writing the script I thought that maybe someone else would direct it, but then I started to fall for it so much that I left the other project and I put all my time on The German Doctor.

Much more than trying to focus on the battlefield of the war, it was the central place that German doctors occupied within Nazism, the omnipotent and insane idea of wanting to generically modify an entire nation. This idea was not on the outskirts of Nazi ideology, it was the heart of movement, that's what intrigued me. Mengele is the most extreme expression of this idea.

In general, even if I'm dealing with a historical subject, I begin with invention rather than investigation, because I need to understand what is going to be the voice or the tone of the story.