The Departed are strange "carbon copies" of "lingering memories" normal humans leaves behind when they pass away. They are normally tied to the place in which they were buried or where their ashes were held, and their existence "expires" after a lengthy passage of time (around a century). Their appearance can be younger from their actual age of death, but not older; whether this is controlled behavior or a desire by the dead person is unknown.
They have no physical body, and are unable to collect Ether as Strays would, however, they are able to react to certain specific forms of Ether, such as the one that Sanae Fujiwara possesses. Occasionally, such Ether may "invite" Departed beings into residences, but this is usually limited to the immediate relatives of the people who once lived in those residences, and such an effect is usually temporary. As these beings are carbon copies of people who have passed away normally, they do not have any desires to do much and usually interact with their surroundings (and fellow Departed) as though they were part of an extended, undisturbed afterlife community, doing nearly exactly the same things they would have done as the people who "created" them upon their deaths.
Who creates Departed?Edit
Normal human beings who pass away in a comparatively normal situation to that of any Stray is very likely, but not absolutely, to create a Departed copy of himself/herself. Complete sentience, however, is required to create a Departed, which is why a Panzer that passes away in the same fashion, being the hybrid of an animal and a human, does not leave behind a Departed.
Being carbon copies of dead human, they are able to "recollect" the lives of the people whom they were copied from; being aware that they are not humans, a Departed may also open up to express their feelings about the people they left behind. Motivated by proper Ether, they can potentially become the eyes and ears of the Ether's owner, and report situations accordingly. How accurate this is, however, greatly differs from region to region (where the Departed exists) and sometimes, even in between the reporting Departed, as situational accuracy varies drastically from Departed to Departed. For example, where a Departed scientist may be able to identify specific kinds of flora and fauna found in the area, a Departed lieutenant of the military may instead identify vantage points and strategic areas to defend, and automatically provide more information such as hostile numbers and types.