Earth-Man

Earth-Man is a powerful supervillain from DC comics who held a grudge against the Legion of Super-Heroes after being rejected and would resurface as a major threat to world security.

Earth-Man tricked the world into believing that Superman was not an alien but a human given powers to protect humanity from aliens - using this lie Earth-Man began to turn humanity extremely xenophobic towards all aliens and even leaving the United Planets.

Taking full advantage of the situation Earth-Man had all aliens of Earth violently captured and deported before gathering like-minded villains to form the Justice League of Earth : who upheld "Superman's beliefs" (in reality Earth-Man's destructive xenophobia).