Death (mythology)

Death was a mysterious being and a figure in legends. It was present to Suzie Costello and Owen Harper in the afterlife, and was believed to be a personification of death. Owen stated that it was "duroc," or "hunger."

Biology
In its natural dimension, Death was invisible among the dark void, but its presence could still be felt and heard by the dead there with it. When it entered the universe, Death had the physical form of a human skeleton shrouded in dark grey vapour. Death was capable of communicating with a low, hoarse, whispery voice both in English and in another language, although it was only ever known to say one thing in either language - "Melenkurion abatha duroc minas mill khabaal!"/"I shall walk the Earth, and my hunger will know no bounds!"

The only known method through which Death could enter the universe was if someone were resurrected using the left-handed resurrection gauntlet - after the gauntlet permanently brought the person back in an undead state, Death would feed the person energy to sustain it, while also using the person as a gateway from the afterlife into N-Space. Death would occasionally possess the person, and would gradually change their cell structure. Once the person's cell structure was 100% transformed, Death would fully cross through them into the universe.

In the universe, Death would be capable of instantaneously killing living beings by touch or by coming within very close proximity, draining their life and reducing their bodies to shriveled husks. Though it could apparently kill any living being this way, Death preferred and was drawn to the dying and near-dead. However, Death could only temporarily kill Jack Harkness due to the latter's immortality, and the undead beings resurrected by the gauntlet were completely immune to Death's abilities. When Death entered N-Space via the resurrection gauntlet, it had to kill thirteen sentient beings in order to enter the universe permanently; otherwise, after a length of time, it would vanish back into the darkness in a burst of energy. (TV: Dead Man Walking)

Biography
According to Suzie Costello, when one died and entered the afterlife, Death would stalk them in the darkness. (TV: They Keep Killing Suzie)

Death was both worshiped and feared by Weevils. Once in 1479, it manifested itself in Cardiff after a girl named Faith was brought back to life with the resurrection gauntlet. Death killed twelve people, but Faith managed to stop it before it could collect a thirteenth victim, which would have enabled it to enter the universe permanently.
 * During this time, contemporary chroniclers also recorded the presence of Weevils, which seemed to have inspired imagery of the Grim Reaper.

In the early 21st century, when Owen Harper was resurrected with the same gauntlet, Death used him as a gateway into the universe, and possessed him repeatedly. While doing so, it repeated "I shall walk the earth and my hunger will know no bounds" in a strange language.

Eventually, the energy from Death that was keeping Owen animate fully transformed Owen's cell structure; allowing Death to cross through into the universe. After manifesting in the universe through Owen, Death had the physical form of a human skeleton shrouded in grey vapour. It travelled to St Helen's Hospital and began killing and collecting the souls of the staff and patients that Torchwood failed to evacuate from the hospital in time.

Death claimed twelve of the thirteen souls it needed to fully enter the universe, but before it could claim a thirteenth victim, Owen used faith to literally fight off Death and dissipate its energy; sending it back to the darkness. (TV: Dead Man Walking)