A type of serial killer who is employed as a caregiver and kills people under their care.
A shinigami.
The Grim Reaper.
An angel which attends to death, collecting souls at death, ending life at the appointed time of death.
Azrael.
Death, one of the Four Horsemen of the Apocalypse.
The fact of something being lethal; the ability of something to kill.
The degree of lethal (mortal) danger that something (usually a disease or a weapon) presents; the magnitude of its power to kill organisms exposed to it; this property is indirectly measured by any of various proxy rates, including mortality rate, case fatality rate, or infection fatality rate (for diseases) or kill rate (for weapons, pesticides, or parasites).