Four Axi-Tun explorers crash-landed on Earth and were enslaved by Nazi scientist Werner Schmidt, who named them after Teutonic gods. The four Axi-Tun battled the Invaders and then committed suicide to prevent Axi-Tunian technology to fall into human hands. Year's later, Axi-Tun warriors calling themselves "The Four Horseman of the Apocalypse" attacked Earth but were repulsed by the Fantastic Four.