Death Reapers

Death Reapers are beings from the Luminous Netherworld that take the souls of those who have died to the Luminous Netherworld and/or Mortis.

Appearance
Death reapers appear to be winged boys (of an unknown apparent age) in loincloths who carry swords. They are capable of flying at nearly the speed of light.

Powers and Abilities
Light-Speed Travel: Death reapers can fly at nearly the speed of light

Teleportation: If "The Figure" was a death reaper, it was capable of creating some sort of portal

Psychopomping: Death reapers can carry souls to the Luminous Netherworld, or perhaps Mortis

Known Death Reapers
The one Khi saw when Max died looked like "a winged boy wearing a loincloth and carrying a sword at his waist, flying toward the frozen planet of death almost at the speed of light."

It is possible "The Figure" Khi and Nessa saw in the Temple of Azatalan was a Death Reaper.

Trivia

 * They are described similarly to the Greek Mythological Thanatos, the Greek god of death. One such depiction is a winged and "sword-girt" youth.
 * Max refers to them as angels. It is unknown if they are angels or connected with angels, or simply resemble angels, leading to a misconception.