Green Skull

In the 1940s, Lex Luthor was a renowned entrepreneur and philanthropist who resided in Metropolis. He was married to Lois Lane, a war correspondent he met at a charity ball. Widely considered to be a model citizen and contributer to society, Luthor was also personal friends with high-ranking political figures such as Winston Churchill and president Franklin Roosevelt. Only Super-Soldier, a World War II-era superhero created by the U.S. Government, saw through his facade and knew that Luthor was actually a corrupt war profiteer who was aiding the Nazi Party in an effort to prolong the war.

While looking into the secret government project that created Super-Soldier, Luthor learned of an alien craft that landed in Kansas and carried a radioactive ore known as Green K, or the "Kansas lode". In 1938, he arranged for Nazi scientists to steal the ship and its cargo for him. Observing that the green meteorite endowed Super-Soldier, Luthor created a serum for it, which he injected into himself. The result greatly extended his own lifespan, but inadvertently turned him into the cadaverous Green Skull.

Seeking to remove Super-Soldier, the main asset of the Allies, Luthor designed Ultra-Metallo, an enormous robot powered by the meteorite "Green K", which became the chief weapon of the Axis powers. Both the robot and Super-Soldier engaged each other over a fleet of allied battleships. After a climactic battle, they both sank to the bottom of the Atlantic Ocean. Luthor's second invention was the K-Bomb, an explosive composed of Green K, which he freely handed over to the Americans. As expected, the K-Bomb was quickly deployed, allowing Luthor to cut his losses and bring a swift end to the war. The detonation of the bomb also blanketfed the Earth in radiation, to which only Super-Soldier was susceptible.