Promataus was one of the first earthen created, and was the ancestor of all those who resided in Uldaman - making him the forefather of todays dwarves. For hundreds of years he assisted his makers in shaping the world and delving the deep places, and eventually became the first chieftain of what would become the Ironforge clan. He was the one to recieve the Iron Forge itself from Khaz'goroth, along with his cousin from Ulduar who recieved the Stone Forge. During this time he obeyed the Titans without question, until the time came for them to move on to another world.
As the Titans prepared to leave, the earthen realised that without the powers wielded by the Pantheon life would soon cease to exist. Most important of all was the ability to take control of the fires of the earth, without which they would freeze to death in the cold caverns that were their homes. But none of the earthen were prepared to risk the Titan's wrath by attempting to steal the secret of fire, save for Promataus who felt that the future of the clan rested in his hands.
As the sun set on the final day of the great work, Promataus crept into the camp of Khaz'goroth and absorbed that part of the giant's memories which revealed how to manipulate it. But as he left again, he caught the attention of two sentries who saw the glow he carried out. They pursued Promataus all the way back to Uldaman, where they finally caught him. But in that moment he passed on the secret to the other earthen, who then fled back into their caves where their creators could not harm them.
When he met with the Pantheon, Aman'thul wished to destroy the rebellious earthen for daring to take something which would have been given freely. He instructed Khaz'goroth to flood Uldaman with magma, in the hope that the stone-skinned creatures would melt in the ferocius heat. But Khaz'goroth was merciful, and secretly bestowed the earthen with the ability to resist heat. Together with their new knowledge, most of the earthen were able to survive.
As for Promataus, he was sentenced to spend the rest of eternity in a prison deep below the highest mountain in the land. And since that day the first chieftain has not been seen. He may have died in the sixty thousand years since, or he may still be alive and waiting for the Second Coming. Perhaps he long ago tunneled out and now wanders the halls of Uldaman searching for a cure to the Curse of Flesh.
He is based upon Prometheus from Greek mythology. Just as Promataus stole fire from the Warcraft pantheon of Titans, Prometheus stole it from the Greek pantheon of gods.