Titan - Titan Crew: The commander of a Titan is an individual who is a member of the Adeptus Mechanicus' Collegia Titanica called the princeps, a rare individual in that they can retain their sanity after connecting with the "Machine Spirit" (computerised artificial intelligence) of the Titan through an MIU (Mind Impulse Unit) neural interface. The princeps controls the Titan by means of the mental link provided by the MIU.Using this ancient technology, the princeps merges his or her consciousness with the Titan's sentient "Machine Spirit" -- its artificial intelligence. The Mind Impulse Unit enables this link by creating an interactive and immersive sensory space -- sometimes referred to as "the Manifold" -- in which the princeps can comprehend their war engine and their environment when they become the towering war engine.The Titan is operated, in enforced cooperation with the Machine Spirit, through mental commands issued in the Manifold by the princeps. Such neural enmeshing is extremely taxing, and most princeps cannot bear the strain of controlling all of a Titan's systems -- and those who do, only can for short periods of time. Thus the princeps must be assisted in operating the war machine by junior officers called moderati, whose purpose is to operate some of the Titan's systems in their commander's stead.To establish the link between the Machine Spirit and the Human mind requires that the princeps submit to extensive cybernetic augmentation of his or her central nervous system, either by accepting the implantation of several cybernetic implants at the back of the neck and skull, a series of implants in the spine which enable the linking of the MIU to the spinal cord or even undergoing entombment in an amniotic tank with large parts of the body rewired to accomodate cybernetic interaction with the Titan. Additionally, some Titan Legions utilise auxiliary haptic connectors, though others discard such measures as too delicate and too easily compromised to be placed in a war engine.As mentioned, some Titan princeps are interred within an amniotic tank, a device filled with a jelly-like polycarbon fluid in which the individual is suspended, and equipped with augmitters and vox-casters which allow the person within to communicate with their surroundings. The device acts as a complete life support unit, handling all of the vital bodily functions of the princeps within. The fluid's function is to suspend the individual within the casket, greatly lessening the strain on their nervous system, and to create a stable neurochemical environment. Most usually, it is also a carrier of nutrients and oxygen, and in such a case the Human within is modified to breathe it through his or her lungs.Sometimes, however, the fluid does not fulfill this function, and in this case the life support unit will provide external blood oxygenation and removal of excess carbon dioxide, which is then once again supplied into the body and into the right atrium. To facilitate such a change, the princeps' heart will possess an artificially created foramen ovale -- a hole between the upper chambers of the heart, allowing the blood flowing into the right atrium to bypass the lungs -- which perform no function while in the tank -- and enter the left atrium, from where it flows into the left ventricle and is further distributed across the body. Such an artificial circulatory system, as well as the body's suspension in amniotic fluids, closely resembles that of a gestating foetus within its mother's womb.Due to their near-complete uselessness, the hands and feet of a princeps interred in an amniotic tank are sometimes amputated and replaced with augmetic haptic sheaths that serve as a part of the broader Mind Impulse Unit. In addition, the eyes are occasionally removed, and the sense of sight, along with others, is replaced by the sensors and auspexes of the Titan and those built into the amniotic casket. Eye sockets then serve as another medium of connection for the individual to the Mind Impulse Unit, possibly making use of the conveniently placed ocular nerves. The cybernetic link created via an amniotic interface is much deeper than that attained using hard-plugs, which makes disconnection from the MIU much harder. It is a complex ritual that can only be performed by a senior Tech-priest, and if not carried out appropriately the princeps in question can suffer severe mental and neural trauma.Internment in an amniotic tank allows the princeps within to enmesh with the Titan's Machine Spirit more completely than they would ever be able to utilising only hard-plug connection. This greater and even more immersive connection grants an advantage in comprehension of the war engine and speed of reaction over a princeps using the more traditional connection methods. A princeps utilising amniotic interfacing is also at all times in remote communion with their war engine, even when the Mind Impulse Unit is deactivated and the Titan itself is shut down.Because of this permanent neural connection, these princeps suffer none of the symptoms of withdrawal or the pain of separation which are the domain of pilots using standard hard-plug connection. However, due to this constant mindlink, and because of the atrophied state of their bodies, they are more exposed to the Mind Impulse Unit's effects on the psyche. This is only natural, for as the body atrophies and grows weaker from lack of use, the mind further withdraws into the depths of the Manifold and the personality is degraded. The Human within slowly but surely is detached from their Humanity, and eventually becomes nothing more than a dysfunctional part of the machine, their consciousness lost in the artificial mental landscape created by the Mind Impulse Unit.For this reason, many princeps hesitate to embrace amniotic immersion despite its advantages and fear the consequences it would bring, while some other members of a Titan's crew view such individuals with a measure of unease and uncertainty. Still, amniotic interfacing offers considerable advantages, and for this reason its use is standard practice in some Titan Legions, and some patterns of Titans require it by design.Princeps will also be modified for internment in an amniotic tank in order to save their lives, for example after they sustain great physical or mental trauma, as often occurs after surviving the destruction of a Titan, or when their addiction to the link grows severe enough that they may not be able to bear disconnection from the MIU. Amniotic immersion is then used to preserve their ruined bodies and to keep their sanity intact through the permanent connection to the Mind Impulse Unit it allows.When the princeps is linked to a Titan's MIU, they feel the Titan's body as if it was their own -- their hands become weapon arms, their senses are turned into powerful auspexes and their skin becomes the thick adamantium hull -- an experience of supremacy and escape from Human frailty that addicts every princeps to his or her link with a Titan. The princeps is then able to command the Titan intuitively -- they merely need to think of undertaking an action and the machine complies.During this operation, the princeps does not lose conciousness of their own body, and is able to simultaneously move and act as normal within the Titan's cockpit. It requires a strong will to maintain this connection, and Titans can go out of control on rampages of destruction should their princeps fail to maintain dominance over its sentience. Particularly ancient and war-worn Titans are known to hold neural imprints of all their previous princeps' personalities in their Machine Spirit. There has also been noted rare instances where a princeps has died while connected to the Titan, thus creating a digital "ghost" of themselves that remains inside the Titan's Machine Spirit. This is often referred to as a "ghost in the link."The process of linking the Human mind to a god-machine is very difficult and dangerous, as a Titan is possessed of a ferociously potent Machine Spirit; one that is unlike any other, harbouring its own savage and instinctive intelligence. The princeps must break the machine's instinctive opposition to control and bind it to their will -- a feat requiring enormous willpower. Because of this, princeps are rare individuals, and one of the tasks the Collegia Titanica carries out is to discover them wherever they can be found and train them to command the colossal war engines.Whilst normally the Adeptus Mechanicus searches for its personnel within the faithful of the Cult Mechanicus, the sheer rarity of such individuals requires the Mechanicus to search in the broader populace of the Imperium. Barely one in ten million possess the necessary qualifications and mental abilities to serve as a princeps, and even fewer of this number make it through the training to finally command a war engine. Because of this reality, princeps are immensely valuable individuals, and their home Forge World will spare no effort to recover them should they go missing in action, and if the slimmest chance exists that they are still alive. There are two ways in which one can become a princeps -- undergoing training in Collegia Titanica academies, as mentioned above, or advancing from the rank of a moderatus to a full princepture, which is usually the command of a Warhound-class Scout Titan.There is also a perverse effect to the mind-link: it is highly addictive to the Human mind. From the moment they manage to dominate their Titan's Machine Spirit, the princeps will actively crave being linked to his war engine, for the feeling of becoming a godlike machine of destruction is impossibly intense, and living as a mere Human eventually becomes intolerable for some princeps. Alas, this withdrawal also accelerates the princeps' descent into madness, straining their mind when they are not linked to their mighty war machine. If a princeps does not fall in battle, they will ultimately fall to the Machine Spirit of their Titan when their will finally snaps.Being linked to the Titan's Mind Impulse Unit is a considerable effort in itself, and controlling the war machine's systems precisely is difficult. Most Princeps are incapable of controlling all of a Titan's functions simultaneously due to the sheer, unbearable mental tumult it inflicts, and those who do will only do so for short periods of time. For this reason, princeps are assisted in operating these towering war machines by junior officers called moderati -- whose role is to operate some of the Titan's systems in their commander's stead -- lessening the mental strain placed on the princeps and allowing for the efficient handling of the machine.The mind-link is a very intimate and immersive connection, causing the princeps and the Titan to leave an imprint in each other's consciousness and grow increasingly alike over time. The Titan's Machine Spirit will learn from its princeps and from the battles they take part in, storing the knowledge and making it available at all times and to any princeps that will command the war machine in the future. The princeps on the other hand, will, with time, begin to show traits of character akin to those of his or her war engine.The nature of the Machine Spirits varies between individual Titans, however war engines of the same class will be similar. Thus, the commanders of Warhound-class Scout Titans are known to be bellicose and belligerent, and sometimes loners, though the latter may be due to their generally solitary assignments as scouts, while the princeps of other war engines are more cool-headed and better capable of cooperation as part of a larger force.The princeps is seated on a command throne in the Titan's head, along with their moderati several system controllers and second-line bridge officers who act as the Titan's command crew. Lower-ranking officers called "steersmen" who are not in line to ever become princeps often control the Titan's most basic functions like locomotion. The number of moderati and steersmen depends on the size of the Titan, and their duties involve secondary tasks like regulating and maintaining the massive walker's weapons and other systems, as well as monitoring and interpreting readings from the Titan's auspexes (complex arrays of various types of sensors). All Titan officers who are expected to serve as princeps begin their career at the Collegiate Titanica on Mars where they are trained in how to pilot and interact with a Titan as well as many of the doctrines and rituals of the Cult Mechanicus.Other Titan crew members include various engineers (usually Adeptus Mechanicus Tech-priests) for repair work and the necessary blessings required by the Cult Mechanicus, and servitors who are set on the more mundane tasks required by the Titan like the manipulation of controls and the monitoring of the external auspex systems. Some of the largest Titans also have Adeptus Mechanicus armed forces like Skitarii or Praetorian Servitors on board in case an enemy attempts to board and take control of or destroy the Titan.