The Cold (Interference)

The Cold is in fact two different substances; the skin of The Cold and the Cold itself.

The Skin of The Cold
Guest, Compassion and Kode sell The Cold as a weapon on Earth in 1996, which can remove subjects from the physical universe.

If a subject is introduced to The Cold they are taken out of space time and held in stasis with no ill-effects to the subject.

Fitz Kreiner was sprayed with The Cold whilst in 1996, it wasn't until six hundred years later on the colony Ordifica that he was released.

The Cold itself
The Cold believed by The Remote to be a loa, one of the spirits worshiped by the Faction Paradox. However it is in fact a validium based weapon which exists on the boarder between universes.

It has been seeping out through the centre of a giant Time Lord warship, upon which the Faction Paradox had situated a Remote colony; Anathema on.