Kalins were a non-humanoid, technologically inventive race native to the rogue Balant planet.
Background
Kalins were physically indistinguishable from their neighbors, the more aggressive Balants. They had reddish-orange skin with a natural light-yellow bioluminescence. They were about six feet tall, with flat, oval heads. They were a digitigrade lifeform, and their legs had extended metatarsals and three phalanges. Their hands had one thumb and two bulbous digits.
Kalins could fly by harnessing wide, invisible rays within the planet's atmosphere.
A vast gas cloud surrounded the Balant planet, and severely restricted the use of mechanical power. Kalins were able to harness electrical energy generated by native trees to power a force field generator. The generator was used to defend their settlement from meteor bombardment and attacks by Balants. The cloud formed a membrane around any powered energy sources, so that their city was permanently encased by a thin, black covering. (TOS comic: "Skin Deep")
History
In 2266, James T. Kirk and Spock discovered a Kalin city just as it was about to be bombarded by meteors. Kalins deactivated their force field long enough for Kirk and Spock to enter. Afterward, Balants buried the city under piles of meteorites, then attempted to commandeer the USS Enterprise. David Bailey and Hikaru Sulu used phasers aboard the Galileo to clear away the debris. (TOS comic: "Skin Deep")