The origin and home planet of the Cetans is shrouded in mystery. The Cetans are the first alien race to have contacted humans, at least during recorded history. The information is still partly classified, but the Cetans are believed to have first contacted US government around the time of so called Roswell incident in 1947.  Since then humans have made contact with other alien races, but  the Cetans are the only alien race allowed on Earth.

Their social organization resembles more organized crime than anything civilized. Though they trade in technological innovations where it suits their purpose the technology they offer is probably all stolen from somebody else. There are rumors that the so called alien abductions on earth are carried out by the Cetans who need a host species to carry their eggs. There is no evidence for this, but the Cetans seem to come in only one sex.