A specter is a creature of Twilight driven wholly by Spite. Some scholars of the Ministry and DSR compare them to corrupted code or malware building up in a computer system. They are universally hostile and inimical to human life, feeding upon deaths (the more at once, the better). Like spirits, some are low-intelligence – though unlike blips, these minor specters will act on hunting instinct rather than looping actions. Some, however, are extremely intelligent, capable of long-term planning and even imitating a prey's loved ones.
Specters share a hivemind when grouped together, and build themselves homes within Chambers corrupted by the presence of local Infrastructure. These specter hives resemble those built by termites or wasps, but built from all manner of psychic detritus. There is even some evidence that the hive in which they dwell may be a specter (or specters) in and of itself, connected to the hivemind.
A living "device" made of reclaimed specter gauze, the Remora is standard-issue for the Ministry's more senior field agents. It is a combination of communication device, Specter sensor and Spite-powered weapon.
The creature is intentionally rendered mindless via radical psychosurgery to prevent intrusion from the hivemind, though many agents are still understandably leery about using it. It links with the mind of the projector only, obeying commands at the speed of thought.
The Remora is invisible and intangible like a projector's gauze form, and travels with the gauze body when it projects. In Twilight, it can be seen as a hazy, thin, eel-like creature that attaches to the head at the temple and runs behind the ear and coils around the projector's dominant arm, ending in a fleshy attachment on the back of the hand that contains the Remora's Spite reservoir.
Sentien Labs have a particularly horrible tool in their arsenal: leashed specters. These are specters of the lower grades that have been "tamed" to a degree using psychosurgery, and are kept in check by a Stigmatic handler linked to their local hivemind. Great care must be taken to prevent more powerful specters from interacting with this local hive, or the handler can lose control of the weak swarm very quickly.
Sentien deploys leashed specters in carefully controlled numbers (typically 3-5 for a small facility, up to the maximum of 13 at Lab Central) to guard their perimiters from projectors and other intangible intrusions.