Kurtz is a character, not a real man in the history books. He appears in the novel Heart of Darkness by Joseph Conrad (1899). In the story he is an educated white European in Central Africa. He went out with high Western ideas, but he has dropped those ideas and become a violent, powerful ruler — almost a kind of god to the people around him. He is sick, brilliant, and frightening. The book is often read as a picture of what empire does to people, though actually readers still argue about how far Conrad is attacking empire and how far he is still seeing Africa through European eyes. If you have seen the film Apocalypse Now, that film moves the same kind of figure to the Vietnam War and also calls him Kurtz. The novel came first.