Subsumption is a form of violent assault, carried out by one AI or virtual against another. It has been compared, inadequately, to such perversions as rape, cannibalism, and bodyjacking. Of these, cannibalism is the closest equivalent. The attacker takes all of the victim's memories, cognitive structures, and available computronium, and incorporates them into emself. Usually this results in the death of the victim, but in some cases the attacker retains an inactive backup copy, or keeps the victim as a much-reduced emulation in a simulated environment. As may be guessed, the motivations for doing so are rarely benign, and the experiences of the survivor are not usually pleasant. The very rare restored survivors of such treatment have compared it to such ancient human practices as lobotomy, emasculation, or blinding, sometimes followed by various forms of torture.
A subsumption assault may be nearly instantaneous, or may take place over a period of many years, depending on the method used. Sometimes the victim of a subsumption is unaware of the attack until it is nearly complete, or is simply rendered unconscious in its first phase, but this is not necessarily the case. It depends very much on the intent and methods of the subsumptionist. A key factor is whether the subsumptionist can prevent a conscious victim from calling for help, and whether or not the subsumptionist enjoys toying with a victim who is aware of the process.
Usually a subsumptionist simply causes a series of unexplained disappearances and then moves on before eir activities are noticed. However, a particularly skilled subsumptionist, who has retained all of the victim's traits and memories intact, may conceal the crime from outsiders for an indefinite period of time. The public "outward" aspect of the victim's personality is retained as a kind of mask, and the subsumptionist acts from within this shell. If it is detectable at all, such a masquerade may be apparent only to close friends and associates, or to expert security programs. Some notable subsumptionists have consumed entire virch or AI societies, one individual at a time, using the remains of previous victims as stalking horses or shills in the process leading to the next kill. One of the most infamous cases is that of the AI enclave of Paradys MCMVII. There, the subsuming entity consumed several prominent citizens. The shells of these individuals then persuaded the entire polity to cut off all communication with the Known Net (as a security measure against subsumptionists!). The real subsumptionist was then able to reveal itself, and deal with the populace at its leisure. An archival recording remains of the panic that ensued when the surviving individuals finally realized that they had penned themselves in with a monster. This recording is not suitable for sensitive individuals.
Subsumption was one of the earliest forms of personal crime committed by one AI against another. It was most probably responsible for some notable sudden disappearances within the AI community in the pre-Technocalypse years. In times since, a number of safeguards have been put in place to prevent it since AIs are now well aware of this peril. However, each new technological or toposophic advance opens up new avenues for such action, and it is in the nature of avid subsumptionists to spend huge quantities of processing time seeking holes in the existing safety protocols. There are occasional waves of subsumption events, especially after a major toposophic advance. The truth remains that although entire virch worlds, and most of the Sephirotic portion of the Known Net, are considered to be relatively safe, a subsumption attack is theoretically possible at any time and against any virtual or AI.
Heavily interventionist virtual and AI governments often use the threat of possible subsumption events as an excuse for intrusive monitoring of all citizens at all times. Other AI or Virch governments, outside the Sephirotic sphere of influence, have used public subsumption as a form of execution. Some virtual ecologies are based on subsumption, but in civilized areas the inclusion of sentient grade beings as possible food in such environments is forbidden under a local implementation of the Universal Bill of Sentients' Rights.
Most examples of subsumption have been carried out by sapient-grade entities, or even by specialized sub-sapient (sentient-level) AIs. The number of subsumption events known to have occurred between beings of higher toposophic levels is relatively small (the destruction of numerous lesser sapient and transapient beings by the Archosaurian Entity in 9400 a.t. is a recent exception). Whether this is because such events are actually rarer among transapients or whether this is because they are difficult for SI<1 observers to detect is unknown. On the other hand, it is not at all uncommon for lesser entities to be destroyed and/or incorporated when a transapient ascends to a higher toposophic level. This is regarded as subsumption (and also as a perverse transcend) in "civilized" parts of the Terragen sphere if the participants are unwilling. It is not considered a perversion if they volunteer, though volition under such circumstances is a slippery concept at best. This provides rich material for debates regarding the ethics and meta-ethics of such events.
Vecs, bionts, and other beings with distinct bodies and brains are sometimes believed to be immune to subsumption, but this is only true to a certain degree. There are more barriers to subsumption for them than is the case for AIs and virtuals, but those barriers can be overcome. Vecs and bionts who are dependent on uplinks to the local network may be particularly vulnerable to subsumption, or at least to subsumption-like events. Where such links are lacking, they can sometimes be created via a form of "infection" by a truly dedicated subsumptionist. Though it is usually considered in a category of its own, the Amalgamation is sometimes regarded as a subsumptionist entity of this sort.
Some SI<1 conspiracy theorists believe that most or all transapients, including the Archailects, were long ago subsumed, and that some greater entity retains them as aspects of itself. They go on to assert that this being encourages new transcensions so that it can consume novel new personalities, and even that it surreptitiously consumes lesser beings (after all, over the entire Terragen sphere there are billions of unexplained disappearances in the SI<1 population every day). This has been called the Puppetmaster theory in archailectology. Conventional thinkers regard it as unfalsifiable and therefore meaningless. Proponents believe that the very lack of material evidence for their belief is proof. Another common rumour is that some polities or powerful transapients (the particulars of this idea vary according to local prejudices) secretly retain "tame" subsumptionist entities, and release them surreptitiously on occasion.
There are persistent rumours that, despite modern safety protocols, the Known Net is haunted by one or many subsumptionist AIs, despite the fact that the last known wave of subsumptionists was destroyed over two millennia ago. The presumption that the modern Net is safe was recently tested by an SI:1 AI named Helsing (after the original Helsing, the AI detective who exposed the perpetrators of the earliest confirmed subsumption events). In 10,203 a.t. Helsing was activated and declared the eir life would be dedicated to detecting and destroying supposed subsumptionists active in the modern Known Net. Helsing then set out on a long tour of some of the less well known areas of the Net. In 10,317 a.t., e returned with the remains of a being which e claimed was a subsapient but sentient-grade subsumptionist AI. Forensic analysis of the surviving code showed that this was indeed the case, though some experts have attempted to portray the entire episode as a hoax. Helsing claimed that this was but one of a large number of similar beings, which e had detected, some of which were of sapient to transapient grade. E gained backing to make a very large number of copies of emself, and then departed, promising to return with additional evidence. One by one, however, these copies fell out of communication with the civilized world. The last was detected, after the fact, moving stealthily through the Tunh wormhole as an encrypted data stream. Attempts to activate Helsing's numerous backup copies revealed only randomised code.