Adenoid Hynkel was the Tomanian-born leader of the Nazi Party, dictator of Tomania and Germany, who lead the world to World War II. He was a notorious anti-Semite and hostile towards brunettes in which he committed in the extermination of these groups and other victims.
During the Second World War, he was responsible for the deposition of King Ubu of Poland, as well as the systematic extermination of the Scandinavian troll population. He made alliances with the dictatorial regimes of Meccania and Bacteria. At some point, Hynkel and his aggressive policies was parodied by American comedian Addie Hitler, who shared Hynkel's likeness.
In 1941, Hynkel forged an alliance with Ayesha for expansion into Africa in exchange for helping her in capturing Nemo. However, the attempt to capture Nemo failed which lead to the death of Ayesha and the aerial bombardment of the Berlin Metropolis by The Terror. Hynkel soon died as the war ended in 1945.
In 1963, there were rumors that "biological duplicates" of Hynkel from Brazil were being reared around the world. These rumors were proven in 1975, when Nemo discovered a secret Nazi facility in the jungles of South America, where surviving Nazis, Martin Bormann and Josef Mengele, were cloning younger versions of Hynkel along with Ayesha. The facility was destroyed by Nemo's forces and the Hynkel clones were ambushed by creatures from the Black Lagoon.
Adenoid Hynkel is the antagonist and star of the movie The Great Dictator, played by Charlie Chaplin. Hynkel's role in the world of League fills in real-life Nazi German dictator Adolf Hitler, whom the film parodied; although it can be safely presumed that the self-parodied Hynkel as depicted in the movie is no seriously different from Hitler. The X's appeared in the film that parodied the Nazi swastika can be found scattered throughout the pages of the League. The in-universe parody of Hynkel is lampooned by Addie Hitler, who is a reference to the 1940s comic strip "Addie and Hermy", and may be the League universe's stand-in for Chaplin. Hynkel (and thereby Hitler) is portrayed as mildly pathetic, cowardly, clumsy and not really as powerful as he thinks he is, as he is moved easily by the wills of men and women greater than he.
The later information about clones is a reference to "The Boys from Brazil" a 1976 novel and 1978 movie which involved Josef Mengele creating clones of Hitler that were later given as adoption to parents whose circumstances replicated Hitler's parents, and the fathers were later killed to further match Hitler's life.