Biography
The mascot of death. The nature and purpose of the Grim Reaper (also simply known as "Death") varies between two different versions: one version describes him as a simple guide - the supernatural being who takes people to the afterlife when they die (the fancy word for this is "Psychopomp"); another version sees him as the entity of death - he makes people die by touching them or by means of supernatural powers.
Either way, he is generally seen as a tall, often skeletal, specter in a black hooded robe wielding a Sinister Scythe when he visits commoners and a sword when he visits royalty, although the scythe is the most popular of his symbols. He is also often shown with an hourglass as a symbol of elapsing life. These dual accouterments are Older Than Steam, but both were drawn from the ancient Greco-Roman god Χρόνος (Chronos). This god, in turn, was drawn from the Ur-Example of the Sassanid sect's Zoroastrian god Zurvan Akarana. He is sometimes described as mute, and in some accounts you can challenge him to a game of chess for the right to stay alive.
Often he picks up the characteristics of Charon, the boatman of the river Styx in Greek mythology, but even these characteristics are filtered through a Christian veil, i.e. "angel of death". The Grim Reaper, in his days as a frequent figure of folk tales, was originally used as a menacing, somber symbol of the inevitability of death. He first appeared in Western art and folklore with the outbreak of the mid-14th century epidemic called "The Black Death", also known as "the Plague".
As with most folklore-ish characters, he has many and diverse characterizations. He may be sinister or come across as friendly. He may even be played for laughs as a Beleaguered Bureaucrat. Still other representations of death forgo the neutral or buffoonish guise and make Death a God of Evil that must be fought, i.e. Everyone Hates Hades. Others go the other way and say Don't Fear The Reaper; instead of evil, he is benevolent.
The Reaper sometimes overlaps or is influenced by the Angel of Death of Biblical scripture, in which case he may explicitly be equated with the Archangel Azrael.
A frequent variation is the notion that instead of the Grim Reaper, there is a Grim Reaper — that it's a position offered to certain people after they die.
When this concept was imported to Japan in the 19th century, they translated the name as Shinigami (while typically translated as "god of death", it is literally "death kami", which doesn't have quite the same connotations). Japanese media then proceeded to play with the character to the point that many shinigami no longer have anything in common with the Grim Reaper, aside from the name. Shinigami are more typically spirits associated with death, rather than being the singular Anthropomorphic Personification thereof. Thus, the concept of being able to defeat or kill Death in combat (Castlevania) or Grim Reaper figures themselves being able to die (Death Note) can seem absurd to Western viewers. If something does take down the Reaper, you may have The Death of Death on your hands.
A subtrope of Psychopomp. May overlap with Destroyer Deity if they're not separate entities. Compare to Horsemen of the Apocalypse — for when the rest show up — and Afterlife Express — when the Grim Reaper is or rides on a vehicle, especially a train. See also Archangel Uriel, Enemies with Death, The Problem with Fighting Death, and Hanging Up on the Grim Reaper. For the Death Metal band, see Death. As with most public services, expect hilarity to ensue if Death Takes a Holiday, unless someone steps up to the task of Relieving the Reaper. A kinder interpretation may portray him as The Sacred Darkness. May overlap with God of the Dead, and the latter figures often draw inspiration from the Reaper's visual motifs.