Though originally humanoid, the ambassador and billions of Gelth were turned into gaseous lifeforms in the Last Great Time War. Eventually, they discovered a space-time rift, which opened up into Gabriel Sneed's mortuary in 1869 Cardiff. The Gelth were naturally attracted to the area, since they could inhabit the gas found in the pipes and emerge through gas lamps. They also discovered that they could survive in the gases in a decomposing human and, as the Ninth Doctor put it, "use it as a vehicle". The Gelth ambassador contacted Gwyneth, Sneed's servant, who had psychic abilities. She thought of the Gelth as angels.