The R'Kaal were a fictitious Delta Quadrant species invented by The Doctor in an effort to disguise his attempts to steal the USS Voyager's warp core in 2378. He was being forced to do so by Zet and Nar, two renegade members of the Hierarchy who had captured Captain Kathryn Janeway. The Doctor later contacted Voyager as Supreme Archon Loth of the R'Kaal, to ask why they had not ejected their warp core. This transmission allowed Harry Kim and Seven of Nine to uncover The Doctor's fabrication. (VOY: "Renaissance Man")