Space Security Service Edit
Mark Seven was recruited by Colonel Marc Forest and Compuvac to become an agent of the Space Security Service. He was appointed as the head of internal and field security. (PROSE: The Outlaw Planet) As the Service required that agents achieve their objectives without regard for sentiment or compassion, (TV: The Daleks' Master Plan) Seven was responsible for the continued loyalty of all agents. (PROSE: Top Secret)
In the late 40th century, Mark Seven travelled with fellow SSS members Jason Corey and Sara Kingdom on the Space Exploration Team mission to the surface of the giant meteorite M5. Within two days, the Exploration Team, which included Sara's brother David Kingdom, had established a pre-fabricated base called Explorer Base One, protected by a force field. They believed the meteorite devoid of intelligent life, but the base was attacked by Daleks whilst the SSS agents were searching the wider area. The only survivor from the crew was David, who was taken captive for interrogation. Discovering the Daleks' secret underground hideout, the SSS agents tried to rescue David and destroy the Daleks, but arrived too late to stop the Dalek ship escaping with their prisoner. (AUDIO: The Destroyers)
Anti-Dalek Force Edit
Mark Seven, Reb Shavron and Joel Shaw were the original members of the Anti-Dalek Force. Shaw was the commander, and Seven and Shavron were his seconds-in-command. The Force initially had no idea that Seven was a nonhuman, but they discovered his android nature when he appeared to die at the end of their first mission. (PROSE: Terror Task Force)
According to one account, Agent Seven was impossible to distinguish from a regular human. His hair was actually resilient fibre that protected head mechanisms from impact; his ears were actually audio detectors that were ultra high powered microphone, sensitive enough to hear a pin drop from over four miles away; and his eyes' vision lenses were miniaturised television cameras that relayed all visual images to his calculator cells, which resembled a human brain with high intelligence levels.
Seven's nose contained an early warning locator, a scent analyser and a magni radar unit which could detect the approach of anything in total darkness. He also had a radicom unit in his right shoulder with enough power to maintain constant contact with SSS HQ. His speech projector used his lips and tongue to simulate human speech, but since his mech-vocaliser consisted of variable mechanical voice chords, he could perfectly impersonate any nonhuman voice or sound.
As substitutes for human muscles, Seven's muscular units contained powerful electric motors. He could lift eight tons with one hand, and he could maintain sprint speed for over 100 miles. While his electro cells were self-charging, when they were discharged, his motive power would run out and he would appear to be tired. (PROSE: Top Secret)
According to other accounts, Seven was easily distinguishable from other humans due to his pedantic speech patterns. He was equipped with a loyalty circuit, an emotion circuit subservient to his relentless logic, and an infraspectrum-sensitive vision circuit. (AUDIO: The Destroyers)