Kiley
The Kiley were a pre-warp humanoid species native to the planet Kiley 279.

History
Kiley civilization was divided into two factions, the establishment Eldredth and the revolutionary Palion, who have been opposed to each other for centuries. By the 2250s, the violence between them threatened to escalate into global civil war, and their respective leaders had not met in the same room for a hundred years.

In 2258, Kiley telescopes detected the warp signs of Federation, Klingon, and Kelpien starships engaged in the battle near Xahea. The Kiley used this telemetry to reverse-engineer matter-antimatter reactors. By the following year, the Eldredth faction had constructed a warp bomb, with which they hoped to quell the Palion once and for all. Rumors about the weapon spread by the Palion incited mass protests and civil unrest against the government.

The Federation detected the signature of the bomb and, mistaking it for the development of warp drive, dispatched the  to investigate and potentially initiate first contact. The starship was detected by an Eldredth military installation as a "UFO". The Archers crew, consisting of Commander Una Chin-Riley, Lieutenant , and Ensign Hadad, were captured after they beamed to the surface.

The  subsequently arrived at Kiley 279 and came under attack, though Captain Christopher Pike ordered deflector shields raised in time to avoid damage. Pike and Lieutenant Commanders Spock and La'an Noonien-Singh disguised themselves as Kiley and infiltrated the secured underground facility where the Archers crew were being held.

After learning how the Kiley developed the warp bomb, Pike concluded that Starfleet had a responsibility to remedy the situation. Revealing himself, Spock, and the Enterprise to the Eldredth leader in violation of General Order 1, he compelled her to meet with her Palion counterpart. The talks were at an impasse until Pike showed the Kiley population the devastation that Earth had suffered during World War III, and offered them the chance to avoid that eventuality and join the Federation. Opting for peace, the now-united Kiley began learning about the interstellar community and researching space travel. ()

Biology
The Kiley were externally characterized by thickened eyebrow ridges with dark striped markings; their arms and legs bore similar patterns. Their eyes had light blue-green irises. Internally, they had several organs not found in Humans or Vulcans. ()

Society and culture
The Kiley level of development was comparable to that of 21st century Earth. They used automobiles and aircraft, and enjoyed televised mass media. They possessed low-yield plasma torpedoes capable of reaching spacecraft in orbit, but beyond that had not engaged in any space colonization, and they had no knowledge of subspace communications. Their soldiers were armed with projectile weapons.

Tagball was a popular Kiley sport, which included professional teams such as the Cone Rockets and the Boom Shield. ()

Individuals
 Unnamed Kiley

Species