Klingon guard 1
This Klingon was a prison guard at Rura Penthe in 2152. He used a pain stick on Kolos. Archer attacked him and used the pain stick on him. After subduing Archer, he threatened to have Archer spend the night on the surface where no one survives. (ENT: "Judgment")
Klingon guard 2
Klingon guard 11
Klingon guard 14
In 2293, this Klingon commandant was the commander in charge of the penal colony on Rura Penthe. The Commandant was also part of the Khitomer conspiracy and was ordered by General Chang to allow James Kirk and Leonard McCoy to make an escape attempt so they would appear to have been killed while trying to escape. The Commandant captured them escaping as planned and was about to tell them who wanted them killed before executing them when they were beamed aboard the USS Enterprise-A. (Star Trek VI: The Undiscovered Country)
Klingon guards at mines
Klingon mine guard
Alien prisoner #1
Alien prisoner #2
This humanoid species was noticeably taller and stronger than most. One of them was incarcerated at Rura Penthe in 2293 and was an acquaintance of Martia. When Captain James Kirk and Doctor Leonard McCoy first arrived at the prison the Behemoth alien seized Kirk, picking him up above head-level and demanding both his "allegiance to the Brotherhood of Aliens" and his coat. Kirk was unable to understand him as his universal translator had been confiscated. The behemoth later backed off at Martia's insistence and Kirk was allowed to keep his outerwear. (Star Trek VI: The Undiscovered Country)
Blue-skinned Alien with pointy ears
Frozen Klingon prisoner
This Klingon prisoner froze to death, when he was brought to the surface as punishment in 2293. His corpse was seen by Kirk, McCoy and Maria when they escaped the prison camp. (Star Trek VI: The Undiscovered Country)
This prisoner was brought to the surface of Rura Penthe to demonstrate that no one could survive on the surface. He was barely clothed and frozen within minutes. The commandant told the arriving prisoners including James T. Kirk and Leonard McCoy that they should work well and they would be treated well and if they would work bad they would die. (Star Trek VI: The Undiscovered Country)
This humanoid species had blue, scaly skin and horns of varying size protruding all over their heads. One of these aliens was imprisoned by the Klingons at Rura Penthe in 2293 and got into a fight with Captain James Kirk. When Kirk was able to incapacitate the alien with a kick to both knees, Martia pointed out "not everyone keeps their genitals in the same place." As a gesture of truce, Kirk tells Bones to help the creature recover so there won't be any lingering hard feelings. (Star Trek VI: The Undiscovered Country)
The member of this species that Kirk encountered on Rura Pentha had obvious tissue damage to the right side of it's face, making the flesh there appear red in color. Additionally, the horns and other scaly growths also appeared damaged. When Kirk delivered the kick to the creature's genitalia, the creature's blue skin appeared to glow slightly in some sort of painful and emotional response to the blow.
Klingon mine workers
Prisoners in mine shaft
Ragged Klingon prisoner
Tall Klingon prisoner
The individuals present at the Klingon prison where, in Star Trek VI, Kirk and McCoy are detained were originally to have included some characters they had met previously, in Star Trek: The Original Series and the first five Star Trek films. (The Making of the Trek Films, p. 106)
In deleted scenes from Star Trek, Klingons captured the Narada after the USS Kelvin crashed into it and imprisoned Nero for the next twenty-five years. These Klingon guards wore helmets and thick coats, which costume designer Michael Kaplan respectively modeled on a horseshoe crab and elephant and rhino skin. J. J. Abrams said the masks allowed them to avoid selecting Klingons that did or did not have the augment virus. According to him and the producers on the audio commentary for the deleted scenes, the Klingons come up to Nero in large numbers and throw him a chain to cuff himself because they're actually scared of him.
The Klingons in the deleted scenes were portrayed by Victor Garber, who played the interrogator, stuntman T.J. Storm, and background actors Terryl Daluz, Brandon Stacy, Scott Trimble, and James D. Weston II.