Dirk Slipstream

Dirk Slipstream was a criminal who served time in Volag-Noc after being caught by the Doctor in an earlier incarnation. He was sentenced to fifty years per person he killed duringNinth Doctorst- that's 600 dead working out to about 32000 years. In Night of the Humans, he went searching for the Mymon Key- an object of unlimited power- on the Gyre. Slipstream was torn apart by carniverous Sollogs, after he jumped into a swamp when the Doctor chucked the Mymon key in.

He seems to be a time traveller, as he mentioned seeing a Nanobomb destroying a mountain range when only one Nanobomb existed at the time of Night of the Humans.