Captain Scarlet

"Captain Scarlet, you are virtually indestructible." Doctor Gold, Instrument of Destruction Part 1.

Captain Scarlet, also known by his real identity Paul Metcalfe, is a primary agent of the Spectrum organization in major assignments and as of circumstances beyond the comprehension of man is both a key element in the fight against the Mysterons and virtually indestructibe. As such, that means if he would ever die, he would eventually return back to life through retro-metabalism as a result of being under the control of the Mysterons until Captain Blue intervened during that period of time. As such, he's not only a valuable to humanity in his world, but also those of other worlds if the Mysterons see them as a threat to their schemes or if the situation is dangerous enough to require his assistance.

Background
Born in Winchester, England, UK, Scarlet's mother was Ann Brightman, a British astrophysicist, while his father, Tom Metcalfe, was an American pilot who later joined the International Space Agency. As a boy of ten, Paul watched his father take humankind's first steps on Mars and vowed to follow in his historic footsteps. He studied astrophysics at MIT before joining the US Air Force. But the outbreak of global terrorist wars, which saw the deaths of both his parents, changed his focus.

He transferred to US Special Forces and commanded an elite unit that saw action across the world. His second-in-command was Lieutenant Conrad Lefkon, who became his closest friend. With the end of the wars, a new security organisation was established: Spectrum. Paul was an obvious choice for the new organisation, and took on the codename "Captain Scarlet". His good friend Lefkon was also signed up as "Captain Black".

Scarlet later became Spectrum's special weapon in its "war of nerves" with the Mysterons; a weapon created by the Mysterons themselves when they killed Scarlet during a mission on Mars along with Captain Black. After they had discovered the Mysterons' city, Black fired a destructive shot against it, believing they were under attack. The two men watched in astonishment as the city rebuilt itself, and tried to flee to escape their fate, only to be killed afterwards.

The Mysterons rebuilt Scarlet as an invincible human replica to infiltrate Earth and lead their war against the planet. While under the control of the Mysterons, Scarlet tried to destroy Skybase, but was stopped in his efforts by Captain Blue. Falling down through a plasma stream, Scarlet was killed, but recovered later on in Sickbay, under the astonished eyes of Doctor Gold and other onlookers, and revealed himself to be fully free of the Mysterons' control. Metcalfe's human psyche had survived and regained control of his physical body. Instead of being killed by the power surge, Scarlet was only harmed temporarily, and was restored to life by the genetic mutation of the Mysteron "retrometabolisation" process which makes him virtually "indestructible".

Scarlet is a dedicated Spectrum officer. First and foremost, he is a soldier on the frontline of Earth's defences. However, he is also tormented by what he has become, not fully human. Utterly fearless and dedicated to saving the human race, for all Scarlet's heroism there is one thing that makes him very uneasy – his growing feelings for Destiny Angel, the girlfriend of his late friend, Captain Black.

Abilities
Retrometabolism – so far, Captain Scarlet can survive, and heal from any injuries, even the more devastating ones, although the recovery is never instantaneous.

In a few episodes, it is stated that he can feel a Mysteron's presence, by feeling nauseated and unwell. In the pilot story ("Instrument of Destruction", Parts 1 and 2), it is also stated that Scarlet shared a kind of telepathic link with Captain Black – which is considered by Colonel White as an advantage in the war against the Mysterons that he cannot dismiss.

During the episode "Rat Trap", the Mysterons were able to contact Scarlet and to talk to him, while nobody else could hear them. It is not clear if this phenomenon was because he was on the Mysterons' home planet, or if he would hear them, wherever he might be, if they chose to contact him again.

In "Chiller", it was revealed that, when particularly badly wounded, Scarlet's body has the capability to separate his emotional and physical selves so that the latter can heal quicker, leaving the former as a ghostlike apparition, detectable only by its coldness.