The council of Elysia includes an Orion woman, a Romulan, a Klingon, a creature that has bat-wing ears and looks like the original version of the Kzinti as they appeared in illustrations in Larry Niven's "Known Space" book franchise, an Andorian, an unknown insectoid race (possibly the inspiration for the Xindi-Insectoids from Star Trek: Enterprise (2001)), a Phylosian from The Infinite Vulcan (1973), an unidentified humanoid female wearing an environmental helmet, a Vulcan, a Tellarite, a human, and a Gorn.
Many of the vessels in the graveyard of ships were unapproved early designs for the insectoid ship from Beyond the Farthest Star (1973).
This marks the final appearance of the smooth-forehead version of the Klingons. Six years and two weeks later, Star Trek: The Motion Picture (1979) hit cinemas with a new look for the Klingons. The look was changed again for Star Trek III: The Search for Spock (1984). Though this look was used in all future Star Trek series, smooth-headed Klingons reappeared in the later-produced Trials and Tribble-ations (1996) (archive footage from The Trouble with Tribbles (1967), edited into a new show) and in Divergence (2005) (when the Klingons are afflicted with Augment DNA).
The depiction of the Klingon character Kuri is reused animated footage of Koloth from More Tribbles, More Troubles (1973).
Nichelle Nichols provides the voices of four different characters in this installment. It is tied with her record from The Lorelei Signal (1973).