The answer is: C. Kurtz
In "Heart of Darkness," by Joseph Conrad, Marlow sails the Congo River to meet the experienced, radical Kurtz. As he travels, he witnesses the Belgian trade company's mistreatment of the local inhabitants. There he also discovers Kurtz's atrocious and savage methods towards the natives. Besides, Marlow mentions Kurtz's powerful position and report to the International Society for the Suppression of Savage Customs, in which he exposes his method: "Exterminate all the brutes!"