Spectres generally lead short, violent lives even in death, and are universally considered fair game to be used as raw materials in Soulforging, the art of using Wraiths and Spectres as raw materials for a magickal process akin to ironworking, to create weapons and other magickal artifacts of immense power.
Those Spectres which have not yet been caught and turned into soulsteel revel in their negative emotions, causing as much pain and suffering among others (both living and dead) as possible, to produce even more negative emotions for them to feed upon. Like the Wraiths they once were, they spend most of their time in the Umbra, although Spectres generally have an even harder time crossing over into Reality and consequently spend even more time in the Umbra, tormenting other souls and wandering the labrynth of the dead.
It is generally believed that the Caal are whatever the equivalent of a Spectre was for whatever race they were before their death, but there are many small but important differences between a Spectre and a Caal. Caal are almost powerless unless they are possessing someone else, while Spectres rarely possess the living or the bodies of the dead, but are very powerful in their ghost-like form made of Plasma.
Behind the ScenesEdit
We never bothered to buy the sourcebooks for Wraith: The Oblivion, so no confirmed Spectre has ever appeared in a Tech Infantry game or story. They're listed here mainly because we do have Caal and Wraiths show up from time to time, so Spectres probably exist as well, just off-screen as it were.