An emissary is created when a human dies without fulfilling one of their strongest desires. At their death, the High Ones can choose to create an Emissary based on that person. Note that the person is not revived, the newly-created emissary is a completely separate being.
An emissary is physically identical to the human it was based on, and has all of their memories up until death. Psychologically, however, the Emissary is an idealized version of the human whose only goal is to complete their unfulfilled desire. As The Black Guardian said, "They are tailor-made [to the desire]. [...] A broken soldier will become a charismatic and brave leader, ready to lead their men into victory".
The emissaries do not age and are affected more slowly by the cleansing light.
It is unclear what happens when an Emissary obtains their desire. The best hint is given through the ending scenario Catharsis, wherein the Prophet does not take the Dreamflower elixer. The narrator in the opening sequence frames the story of Enderal with the question, "What does it mean to be free?" He goes on to say that, "This is the story of one who desired to be free." The Prophet could have desired to be free from any number of things: nightmares, guilt, fear, etc.. During the final moments of Catharsis, the Prophet returns to the dream landscape of their childhood home and sees four tombstones--one for each member of the family, themself included. It is upon touching the tombstone that the Prophet appears to ascend into nonexistence/the afterlife, in other words freed from their desire and Fleshless status.
These emissaries are offially confirmed to exist:
- The Emperor, who leads the quest to destroy the High Ones, but ultimately triggers The Cleansing. (In the current iteration, Grandmaster Tealor Arantheal)
- The Prophet, who uses their extraordinary power to aid the Emperor in their quest. (In the current iteration, The Prophet)
- The Messiah, who opposes the Emperor and ultimately forces them to trigger The Cleansing. (In the current iteration, Taranor Coarek)
These emissaries are never explicitly confirmed, but are heavily implied to exist:
- The Traitor, who works against the Emperor from the inside and ultimately robs them of a Numinos at the last moment. (In the current iteration, Yuslan Sha'Rim)
On Crescent Moon Isle, the High Ones tell the Prophet that only they are an actual emissary; the High Ones claim Tealor Aranthael and Coarek are both self-deluded. This claim is itself suspect, because whenever the High Ones speak to a human they are playing at psychological manipulation, and the Prophet is vulnerable to feelings of insignificance.