The Ancients are a race of enigmatic aliens from a different universe who are in search of a new home.
They first appear in the Farscape episode "A Human Reaction," in which an Ancient named Jack kidnaps John Crichton to test how well humans would react to an occupation of Earth. Although the experiment doesn't go well, Jack tells Crichton that they've successfully relocated in the episode "Daedalus Demands."
The Ancients live in hives and are very advanced, having developed wormhole technology. They have the ability to implant knowledge into another's mind, and they can take the form of anyone they choose.
In the episode "Unrealized Reality," Einstein describes the Ancients to Crichton as "[m]embers of my species substantially modified to live in your realm." According to Einstein, they "catalogue, report, and influence." Their mission is to monitor wormhole activity and prevent any misuse of their power.
