The history of the PK race is shrouded in mystery, as the origin of the species has yet to be discovered. Instead, PK simply seems to have appeared in the eastern quadrants on many planets at the same time. On those planets with extremely cold climates, such as Kanadys and Rigel, well-preserved fossil evidence has shown that, after arrival, the PK began to evolve at an extremely rapid pace, suggesting the usage of advanced genetic engineering and planned evolution. However, evidence suggests that no PK colony persisted for longer than a century, with many falling to basic issues such as starvation and illness.
Debate has long existed over why such an advanced race undertook such questionable actions. A leading theory is that the PK were being pursued by another race or some other type of threat, and that the colonies were a desperate attempt to escape pursuit. This explanation rationalizes the short supply of food and medicine which likely plagued the colonies from the beginning, but does not explain the rapid, planned evolution of the race nor the apparent lack of communication between colony planets.
Another explanation is that the PK sought to increase the vitality of the galaxy as a spiritual or scientific endeavor, and that the colonies were not meant to be sustainable in any form. This would imply that the loss of language and culture which many of PK's successors underwent after the collapse of colonial society was an anticipated or even encouraged feature of development. This does not explain why the original PK genome disappeared, or why the original homeworld has never been discovered.