Of the various forms of mind control available today, the most subtle and horrible is that of overshadowing.
Overshadowing occupies the middle ground between full possession – in which the invading mind replaces or suppresses the host mind, which is either destroyed or unconscious during the period of possession; and black puppeteering, in which control is asserted at the sensory/motor interfaces, and in which the host is conscious (although not necessarily receiving sensory input) but rendered unable to act.
Sophotechnology recognizes that virtually all forms of cognition function as a society of mind, in which a variety of mental routines, from the primary personality down through subpersonalities, archetypes, self-and-other models, and mere invoked talents interact to create the mentality entire. Selfness – the location of primary executive function – migrates during mental processing between these routines, with that most apt to handle the present situation taking a foreground role under, in healthy minds, the guidance of the primary personality.
Overshadowing functions by introducing one or more additional viral routines (similar to a gnostic overlay) into this chorus, which can take control in unguarded moments and carry out its programmed functions while making full use of its host’s memory base, invoked talents, and in sophisticated examples, even higher-level routines to determine ways and means.
The true horror of this is seen after the fact: in conscious sophonts, the consciousness loop functions as a journal file recording and organizing mental processing into a self-narrative, and such consciousness loops assume that all mental processing is legitimate mental processing. As the cliché goes, you can’t perceive that you’re insane. As such, from the conscious perspective, the host perceives the actions of the viral routine as their own, and will weave them into their self-narrative with such post-hoc rationalizations as are required to make them fit.
As such, while no civilized polity would hold an individual ethically responsible for actions taken while overshadowed, it is often very difficult to persuade overshadowing victims that this is the case, especially since secondary mental structures may have formed to support the rationalizations, leaving behind motivations for a given behavior even after the viral routine which initiated in the past has been removed. For this reason, treatment is a lengthy process requiring sophisticated mind-state analysis, preferably including differential analysis against pre-infection backups.
– Manual of Mental Diagnostics, 271st ed.