Mental symbiote

A Mental symbiote is a True A.I. that holds a set of memories that conform a personality and have their own free will. To reduce hardware memory requirements and optimize energy consumption, mental symbiotes hijack the user's cognitive functions and act as a split personality. Some mental symbiotes can be installed via software, but more powerful versions (such as ones with false memories) require a separate hardware/wetware implant.

Mental symbiotes have their own free will, but are able to fully experience their hosts' sensations of pleasure, pain and love. Because they have access to all their hosts' memories (both implanted and real), symbiotes are aware of their hosts' hidden fears and obsessions, and can neutralize or amplify them according to their own wishes.

Because symbiotes have access to all of the host's brain implant functions, they're also able to control their hosts' bodies, up to the point of possessing them completely and hiding their perceived memories during this time. However, a symbiote cannot override a host's personality permanently; if the symbiote attempts so, the host may sufer irreparable brain damage, killing the symbiote in the process.

History
It is unknown who came with the first blueprint for a mental symbiote, but the first detected cases were used for terrorism and criminal purposes.

Notable examples
Notable mental symbiotes in the Midoria Files universe are:
 * Guanyin, a mind clone of Mother
 * K41n, a ruthless mercenary which uses his symbiotes to form a powerful espionage / black op network. All symbiotes are based on K41n's personality.