He was the holder of the family's mining business on Hagal and true to Harkonnen tradition, he was naive, cruel, gruff and defiant, to the dismay of his more humanistic son.
On the family's way to Salusa Secundus he scorned his son for his humanistic views towards the slaves which would harm the business. When they entered Caladan system, their space yaught was attacked by six patrolling cymeks led by Agamemnon. Ulf bravely and defiantly responded to the attack, but the doomed ship was not fit for such circumstances.
Piers was ejected in a lifepod but it was too late for his parents and both perished in the explosion.