Eventually, Atlantis came to be the center of early human civilization. Its king, Orin, ordered the construction of a protective dome over the city simply as a defense against barbarian tribes, but shortly afterward a meteor crashed into the earth, destroying most of the upper world and sinking the city to the bottom of the ocean. Orin's brother, Shalako, departed with a number of followers through tunnels in order to reclaim another sunken city of their empire, Tritonis, whose inhabitants had not survived. After a few years, Atlantean scientists developed a serum that would permanently let their people breathe underwater; as a consequence of the magic used by Shalako in settling Tritonis, the Tritonians were further mutated to have fish-tails instead of legs. Some descendants of Shalako's son Dardanus also inherited his telepathy, which was marked by blonde hair, extremely rare among Atlanteans. Dardanus's son Kordax further had the ability to command sea creatures. After he led them alongside the Tritonians in a revolution against the king, he was exiled, and children born with blond hair, the "mark of Kordax" were generally viewed as aberrations and abandoned to die.