He was a very cruel man, with no regret that humanity kept the Ood as slaves. He would later be transformed into a Ood himself.
At the age of six, Halpen was taken to the Ood Sphere planet where Ood Operations were located. In warehouse 15 he was shown the Ood Brain, incased in an electric cirlce to keep the Ood as slaves for mankind in the 42nd century.
He was soon given his own personal Ood called Sigma and soon became incharge of Ood operations. A few years after he took control of Ood Operations, he began loosing hair rapidly. Ood Sigma would give him Hair tonic to help regrow his hair.
When the Ood began being infected with Red-eye, Halpen arrived on Ood Sphere to oversee their eradication and establish control. When the entire Ood "livestock" were infected with this mysterious disease, Halpen ordered the gassing of all affected Ood, and intended to destroy the Giant Ood Brain to contain the Red Eye and kill the Ood.However, the Tenth Doctor and his human companion Donna Noble had earlier entered the area and were trying to help the Ood. Ood Sigma led the Tenth Doctor and Donna Noble to the Ood Brain for the final confrontation. When his lead scientist, Doctor Ryder, revealed he was a Friend of the Ood and had spent ten years infiltrating the Company to lower the psychic barrier surrounding the Ood Brain, Halpen threw him into the Brain, which devoured him. Halpen was sensing defeat and suffering from intense headaches, Sigma revealed that he had used the Hair Tonic to dose Halpen with Ood graft suspended in a biological compound, turning him into an Ood as punishment for his attitude towards the Ood.
Sigma declared that he would take care and look after Halpen just as he had looked after him when he was human. It can be presumed that when the Ood left the operations compound and built their own city, Sigma would of taken Halpen to live with them.