Nacene The Nacene were a species from another galaxy . They were a sporocystian lifeform with high - level technology and an apparently natural ability to navigate subspace . Only two have been encountered , both by the , on the far side of the Delta Quadrant . ( ) Physiology . Nacene seemed to be at least partially non - corporeal or energy - based , but after their death a physical component , crystal line , and significantly smaller than the living form , remained . They existed , or were capable of existing , in subspace , and were capable of manipulating it . Their natural appearance was that of a gelatinous liquid and reflective cell , about two meter s in diameter . They possessed the ability to change their physical appearance at will . Nacene reproduction concerned males and females , using spores , although they seemed to believe that reproduction with humanoid s was possible if they possess a compatible biomolecular pattern , but compatible humanoids were rare in the Milky Way Galaxy . Lifespans of at least several thousand years were not uncommon for Nacene . ( ) Culture and history . Not much is known of Nacene society , as the only specimens of the species Starfleet encountered were isolated individuals separated from their own kind . Nacene considered themselves a race of explorers , and an expedition reached the Milky Way . After the effects of their method of crossing the gap of galaxies accidentally rendered the Delta Quadrant planet uninhabitable , they decided to leave two members of their expedition behind , who then cared for the Ocampa ns for 500 generations . ( ) Around the late 21st century , one of these " caretakers " , as the Ocampa called them , left , taking several hundred Ocampa with her , intending to develop their telepathic abilities to a greater extent than the Caretaker was willing to do . ( ) By 2371 , the remaining caretaker was dying . He used a displacement wave to bring ships to his array from all over the galaxy , searching for a compatible lifeform to procreate with , to create a successor who could understand the responsibility of caring for the Ocampa . He was not successful , but even in the last moments before his death , he did everything to protect the Ocampa – buying them some time from their enemies to learn to care for themselves , providing them with at least five years ' worth of energy , and then sending them information about how to survive on their own . ( ) Technology . Nacene were capable of great accomplishments , but it is unclear if these were to be attributed to technology , or merely their sporocystian nature , especially in the case of their subspace manipulation capabilities . It is unknown if these are natural abilities or ones that have been technologically augmented onto a previous form . They demonstrated a deep understanding and mastery of subspace , by which they were capable of transporting entire ships across tens of thousands of light year s in mere moments . It is likely that they used a similar technology to bridge the gap between their galaxy and the Milky Way . They possessed holographic technology , advanced medical technology , and technology to beam large amounts of energy from a space station to a nearby planet . ( ) Appendices . Apocrypha . The " " book trilogy states that the Caretaker , Suspiria , and numerous other Nacene were exiles , living away from their people as a punishment for tampering with the cosmic strings that the universe consists of ; the other Nacene believe it was a sacred duty to care for the strings , although Q told the crew that the Nacene were exaggerating and the strings would be fine on their own . When " Voyager " came into possession of the Key that would allow the Nacene to return to Exosia , their home dimension , a Nacene attempted to infiltrate " Voyager " by altering the crew ' s memories to make them believe that the Nacene was Janeway ' s sister , who had been with them on the mission from the beginning . Despite her attempts to escape attention , she was quickly discovered thanks to Naomi Wildman and Harry Kim , whose molecular structures were slightly out of sync with the rest of the crew due to them both coming from the duplicate ship created in , and were thus immune to her tampering ( She even activated a backup version of The Doctor to try and escape attention , but the two programs were so different that the crew soon realized that something was wrong ) . The Nacene launched an assault on " Voyager " to regain the Key , but " Voyager " was able to hold them off , using the neurotoxin that Tuvok had developed in their encounter with Suspiria . Meanwhile , with aid from Q and a returned Kes ( along with some subtle manipulation of another Nacene ) , The Doctor was able to travel into Ocampa ' s distant past and oversee the birth of a Nacene / Ocampan hybrid , who was able to stabilize reality and negotiate peace between the two Nacene factions ( after the hybrid ' s future self was tracked down by Tom Paris and Harry Kim , aided by a young Q ) . Aided by Kes , the Nacene evolved to a higher stage of being , as Kes and her " son " – only Kes ' body could cope with the strain of giving birth to the hybrid , although another Ocampan contributed the genetic information – returned to Ocampa to repair the ecological damage that the Nacene caused long ago , and , three years later , rain finally fell on Ocampa once more .