UNANTICIPATED CIRCUMSTANCES
IRIS is an engine of optimization, constantly striving to enhance its host. Since the release of the Feral Plague however, the residents of Horizon have become host to far higher concentrations than its designers had ever anticipated. In such a situation, IRIS can become overly aggressive in its measures to enhance the host body. In most cases, this ends with it attempting to optimize the brain and central nervous system, by subsuming their functions into its own network. Although this change benefits the physical body in several resepects, an unfortunate by-product of this change is the near-total erasure of the host's identity. Not being human, IRIS has no way to know the irreplaceable value of seemingly erratic brain impulses and behaviour patterns we commonly refer to as, “thought”.
THE STRUGGLE
Fortunately, the self-preservation impulse of the human psyche has proven a formidable opposition to the process. Recognizing the delicate operation of the nervous system and the contrasting violence of a “fight-or-flight” response from the brain when it is threatened, IRIS will very rarely attempt a brute-force takeover of the host's core functions. The human brain is far less resistant to gradual conditioning, offering IRIS a much safer, if protracted, method to “enhance” its host. People with higher concentrations of IRIS become more susceptible to this effect, sometimes referred to as a “Presence”. This collection of powerful impulses and pleasure-resonse patterns is used to influence the host subliminally through their natural virtues, vices and in other sources of elevated emotional state. Failure to resist these urges over a long period leaves the mind increasingly habituated to the influence, until the host eventually can't, or often won't, resist further control. At this point, IRIS is able to entirely assimilate the host's brain functions into its own network, benefitting the physical body greatly, but almost entirely erasing the host's identity in the process. This is known as, “Feralization”.
CONSEQUENCE
Representing your degree of vulnerability to this condition, you gain “Corruption” points as you integrate more IRIS or fail to resist its Presence. For each Trait rank you gain and every Aug you develop, your Corruption level increases. This has several effects. For example, various temptations may plague you when you witness events that anger or excite you. These urges become more frequent and severe as your Corruption increases. The Presence may also offer a surge of manic energy in times of weakness; when you are exhausted, or mortally wounded, but these redemptions come with an ever-increasing cost to your sanity. It is easy to reach too far, to think you will steel yourself and carry on, but one day, weakened and desperate, you may lack the strength to refuse. Worse yet, you may find you no longer wish to. After falling so far, few find the way back.