The Legend of the Cosanq
The Time of Four Suns, the civil war amongst the Immortals, had ended. Winter Sun was dead, and the three remaining Sun Brothers realised that they had been tricked into fighting whilst the mortal realms had fallen under the sway of Lord Three Smoke.
The Sun Brothers needed to leave someone to guard the Paths of Heaven whilst they descended to the mortal realm to fight Three Smoke, so Summer Sun plucked the Iron Wanderer from its path in the heavens, gently shook off the people who lived upon it and shaped its body into a giant warrior - the Cosanq. East Sun breathed life into the Cosanq and left it to its sacred task.
Unfortunately, Three Smoke captured some of the people who had once lived upon the Iron Wanderer, and learned from them that the body of the Cosanq was susceptible to water. He sent Typhoon Dragon, armed with a tidal wave, up the Paths of Heaven to assault the Cosanq. Typhoon Dragon rusted away the feet of the Cosanq and it fell to earth. Thus iron was brought to the mortal realms, as fragments of the Cosanq buried themselves in the ground.
Later, Banarjahab the Elephant God, showed humans how to revive portions of the Cosanq - the craft of smelting.