Grim Reaper

The concept of death as a sentient entity has existed in many societies since the beginning of history. In English, Death is often given the name Grim Reaper and from the 15th century onwards, came to be shown as a skeletal figure carrying a large scythe and clothed in a black cloak with a hood. It is also given the name of the Angel of Death or Devil of Death or the angel of dark and light (Malach HaMavet) stemming from the Bible and Talmudic lore.

Ancient Greece found Death to be inevitable, and, therefore, he is not represented as purely evil. He is often portrayed as a bearded and winged man, but has also been portrayed as a young boy. Death, or Thanatos, is the counterpart of life, death being represented as male, and life as female.

Breton (Celtic) folklore shows us a spectral figure portending death, the Ankou, Usually, the Ankou is the spirit of the last person that died within the community and appears as a tall, haggard figure with a wide hat and long white hair or a skeleton with a revolving head who sees everybody everywhere. The Ankou drives a deathly wagon or cart with a creaking axle. The cart or wagon is piled high with corpses and a stop at a cabin means instant death for those inside.

Supernatural says:

There's a reaper lore in pretty much every culture in the world. Go by different names. It's possible there more than one of them. 

Reapers stop time.
You can only see em when they're coming at you.
Can trade a life for another.