Imagine God and Lucifer having babies and all those babies are being dropped on a planet they co-created. At first they lived in peace. There was balance, but later on they started to live more and more separated. One wanted to be like dad, and the other wanted to be more like eeeh, the other dad?
Some rare folks accepted who they where; both angel and demon. Most, unfortunately didn't. It takes serious courage, you know.
This planet was called earth and the babies are us, humans.
Darkness is not the problem. It never was.
Suppressing it, is the problem.