Tall, fiercely proud warrior tribes of Capella IV, whose topaline deposits drew both the Federation and the Klingons, and who are ruled by a Teer.
The Capellans live in tribes on Capella IV, a world rich in topaline, a mineral the Federation hoped to mine. They are physically imposing, quick to settle disputes by combat and scrupulously honest, and they fight with weapons such as the kligat, a bladed throwing disc.
Leadership belongs to whoever can seize it. In Friday's Child, the challenger Maab killed Teer Akaar while the Klingon agent Kras competed with Kirk for a mining agreement. Maab ordered the death of Akaar's pregnant widow, Eleen, and Kirk, Spock and McCoy fled into the hills with her.
McCoy delivered Eleen's son in hiding. After Maab sacrificed himself to expose the Klingon and Kras was killed, the infant became the new Teer, named Leonard James Akaar after the two officers, and the Capellans agreed to deal with the Federation.