Cyber-Lieutenant

A Cyber-Lieutenant was a rank in the leadership hierarchy of the Cybermen. The Lieutenant served as the assistant to the Cyber-Leader and third-in-command of the Cyber-Force. Unlike the Cyber-Leader, the Cyber-Lieutenant had no markings to identify it.

The Lieutenant always remained close to the Leader during operations or missions that involved the survival of the Cyber-race. The Lieutenant tended to be more cautious than the Leader, often highlighting the drawbacks to the Leader's planned course of action. Even so there appeared to be a strict hierarchy in place; when a Cyber-Lieutenant objected to its Leader's making inaccurate reports to the Cyber-Fleet, the Leader told it that "You are outside your function." (TV: Silver Nemesis)

The Mondasian colony ship
A Cyber-Lieutenant, evolved from one of the hundreds of Mondasian Cybermen created on Floor 1056 of a Mondasian colony ship (TV: The Doctor Falls), served as second-in-command to a group of Cybermen sent from said floor to Floor 0508 of the ship. Under orders from a Cyber-Planner, they attempted to prime a group of Cybermats to attack Floor 0507, as well as capture and  for interrogation as to how and why the Cybermen's definition of humanity had been altered, and who had done so. However, before the patrol trapped the trio, Missy stunned the Cybermen with her sonic umbrella, allowing the Master to destroy the Cyber-Lieutenant with a direct blast to its chest plate from his laser screwdriver. (PROSE: Alit in Underland)

Nemesis
A Cyber-Lieutenant in 1988 assisted the Cyber-Leader in their attempt to acquire the Nemesis. With it and a fleet of thousands of Cyber-Warships, they intended to conquer Earth and turn it into New Mondas. This Lieutenant encountered the Seventh Doctor, and objected to the Leader making reports to the fleet. The Cyber-Leader told him, "You are outside your function." He and a Cyberman that were about to harm Ace were killed when the Rocket-sled's engines fired at them, burning them. (TV: Silver Nemesis)

Start of the Cyber-Wars
A Cyber-Lieutenant accompanied a Cyber-Leader on his plot to destroy the Earth with a Bomb to prevent the alliance forming. The bomb failed thanks to the Fifth Doctor. The Lieutenant and the Cybermen were able to infiltrate Briggs' freighter. Its cargo, unknown to the crew, was an army of Cybermen. They awoke and took over the ship. The Cyber-Leader planned to destroy life on Earth by hitting it with the craft they had reprogrammed. After the Doctor killed the Cyber-Leader, the Cyber-Lieutenant was killed by Nyssa on the TARDIS. (TV: Earthshock)

Saving Mondas
A Cyber-Lieutenant acted as second in command to the Cyber-Leader in their base in the London sewers and also acted as the Cyber-Controller's adviser and reporter. It is unknown if this Cyber-Lieutenant survived or got killed when the Sixth Doctor sabotaged the Cyber-Tombs. (TV: Attack of the Cybermen)

In the Death Zone
A Cyber-Lieutenant, along with a Cyber-Leader and a squad of Cybermen, was Time Scooped by Borusa to the Death Zone. It fired at the Doctor and. The Doctor escaped with the the Master's homing beacon, while the Master tricked the Cybermen into working with him. The Master led a group of the Cybermen to the Dark Tower. These Cybermen attempted to cross a chessboard-patterned floor and were all electrocuted. Meanwhile, the Lieutenant and other Cybermen placed explosives around the Doctor's TARDIS. The TARDIS safely dematerialised before the explosives could be detonated. (TV: The Five Doctors)

Behind the scenes

 * A Cyberman, credited as First Cyberman, previously held a position equivalent to the Cyber-Lieutenant in Revenge of the Cybermen.