Umath found there is no place where he could reign his own kingdom. So he lifted the Sky from the ground to make space inbetween. So he is the primal air.
So it was Umath who brought motion into the universe when it had grown stagnant.
He became the god of Elemental Storm and Orlanth's father.
Umath receives no direct worship as he is considered dead since he was killed near the end of the Gods War. Orlanth is considered his rightfull successor.
He is usually portrayed as a squat, powerful figure holding up the sky.