It seems there may have been a great variety among the Ktarian species. In some cases Ktarians had distinctive foreheads divided into two hemispheres (which seem to have been bones), and distinctive yellow eyes with horizontally slit pupils. (TNG: "The Game")
In the case of a Ktarian/Human hybrid, the resulting offspring could lack the bony forehead structures and yellow eyes, and instead have exo-cranial ridges. A rare complication of these hybrid gestation occurred when the baby shifted position in the uterus and the exo-cranial ridges lodged in the uterine wall. A Ktarian/Human hybrid's gestation period was almost eighteen months. (VOY: "Deadlock", "Fury")
Upon birth, breast feeding could begin immediately; however Human females needed to remain cautious, as the incisors of Ktarian infants erupted within three to four weeks of birth. Because Human females lacked the scales of a Ktarian, alternative measures to protect the flesh were typically recommended. (VOY: "Deadlock") The early stages of Ktarian development were marked by significant growth – a much higher rate of growth than that of Human toddlers. At the age of two, Naomi Wildman, a Ktarian/Human hybrid, grew five centimeters in a three-week period. (VOY: "Mortal Coil")
Ktarians had technology sufficient for the creation of plasma coils as early as the 21st century. (TNG: "Birthright, Part I") However, during the 24th century, their starships were inferior to such Federation starships as the Galaxy-class.
At least one member of this species had been assimilated by the Borg by the 2350s whom the Borg designated as Species 6961. (VOY: "Dark Frontier") Another was a member of Unimatrix Zero in 2377. (VOY: "Unimatrix Zero")
In 2368 the Ktarians tried to gain control of Starfleet. They created a type of mind-control technology disguised as the highly addictive "Ktarian game", and attempted to use it in order to wrest control of Starfleet. The Ktarians almost succeeded in gaining control of the USS Enterprise-D but failed due to the efforts of Lieutenant Commander Data, Ensign Robin Lefler, and Wesley Crusher. (TNG: "The Game")
They also had some popular culinary dishes popular among Federation officers, such as their Ktarian chocolate puff, Ktarian eggs, Ktarian beer, and Ktarian Merlot. (TNG: "Liaisons"; VOY: "Scientific Method"; Star Trek Generations)
While in "The Game" Etana Jol tries to take control of Starfleet while seemingly representing "the Ktarians", in "The Voyager Conspiracy" Seven of Nine stated that "the Ktarians were officially with the Federation, but they sympathized with the Maquis". The latter statement might suggest the Ktarians were Federation members or at least allies, but on the whole their relationship with the Federation remains confused and uncertain.
Several seemingly different species have been identified as Ktarians over the course of The Next Generation and Voyager, with the most notably obvious difference being found in the cranial features seen on Etana, Naomi and the Borg drone.
Etana was described in the script simply as an "alien, gorgeous, with a full, flowing mane of hair."
According to an internal reference document, listing all the aliens seen in Star Trek: The Next Generation, which was circulated around the time of the production of TNG Season 5, the Ktarians were described as "mostly humanoids, slightly enlarged front cranium formed into two circular halves, separated by a shallow crease in the skin."
Regarding design and make-up of the Ktarian, Etana, Michael Westmore shared in two different publications, the following information:
Ktarians – When Etana, a Ktarian, subverts Riker's mind, and the minds of most of the crew, with an insidious game device, the Enterprise finds itself in terrible danger. Part of Etana's ability to lure Riker depends on her dramatic beauty, a beauty that had to be represented visually despite Etana's alien physiology. Makeup was able to accomplish this by enhancing her female facial features. An appliance gave her a high, expanded forehead with bulbs for two large brain lobes. She wore a very beautiful red wig with full, rich hair. Her eyes were highlighted by powerful eyeliner and extra long and think eyelashes, finishing out with seductive full lips. This was the first time we did a creative painting on fingernails. She was a very effective character. (Star Trek: Aliens & Artifacts, p. 117)
When I was creating the makeup for Etana [...] I wanted her to look beautiful and alien at the same time; not always an easy thing.
Because the actress who played Etana had a very high forehead, I decided to create an appliance that would give her a large, bulbous forehead. We added a long red wig, like a lion's mane, to accentuate that look. I applied a total high fashion makeup, including eye makeup, false lashes, and full lips. The idea was that even thought we was from another planet, Riker would still find her seductively attractive.
I also decided to give her a set of long, glamorous fingernails, and spent a long time painting and airbrushing them in hot colors. Unfortunately, we decided to glue them on with a temporary nail glue , and they kept popping off. During her scene with Riker, she spent a lot of time grabbing and chasing him around, so we had to follow her around the set, retrieving the nails and gluing them back on. (Star Trek: The Next Generation Makeup FX Journal, p. 88)
While Etana shared a likeness with the later seen Miradorn – both having double lobed foreheads and similar brow features – she lacked the exo-cranial thorn-like features found on Naomi Wildman – who in turn shared a likeness with Trajok, an unidentified alien. In both Voyager and Enterprise, two female individuals appeared who resembled the "original" Ktarian make-up seen on Etana. For more information on these discrepancies, see the full analysis at Ex Astris Scientia.
- "Deadlock" (Season 2)
- "Basics, Part II" (Season 3)
- "Mortal Coil" (Season 4)
- "Once Upon a Time" (Season 5)
- "Infinite Regress"
- "Latent Image"
- "Dark Frontier"
- "Survival Instinct" (Season 6)
- "Dragon's Teeth"
- "The Voyager Conspiracy"
- "Blink of an Eye"
- "Ashes to Ashes"
- "Child's Play"
- "Unimatrix Zero"
- "Shattered" (Season 7)
- ENT: "Demons"