When Mankind first began colonisation of the stars using conventional sub-light spacecraft, progress was painfully slow. Colonies were separated from Terra by generations, and without guidance and protection, the colonies were vulnerable to alien domination or worse. The discovery of warp drives, which allowed much faster travel through the fluid medium of the Immaterium, accelerated the colonisation of new worlds and allowed the distant systems to become part of a more unified whole. But warp drives alone were not enough to allow rapid, long distance journeys across the galaxy. The Immaterium is the place where the most terrible of spirits and emotions find substance. A nightmare realm where insanity is a living thing and dreams walk clothed in flesh, full of torment and madness. It is an echo of the material universe, with every thought, desire and lust given shape in its fluid, haunted depths. Ships were forced to use short, dangerous and blind warp jumps, risking the ship and her crew with each jump. Without a reliable means of guiding the ship, it was at the mercy of the fickle tides of the Warp, and many of those early voyages ended in disaster. To travel through this realm blindly is the most dangerous of journeys and only the stabilised Navigator-gene (all Navigators have a characteristic 'Warp Eye' on their foreheads) allows the ships of the Emperor to travel in relative safety from one side of the galaxy to the other. The Navigator gene allows a Navigator, with the aid of the Astronomican, to use his warp sight to guide spaceships through the Warp's unpredictable tides.
The emergence of the Navigator Families
Quite how the Navigator-gene came to exist at all is a mystery that none of the ancient Navigator Houses will reveal. Perhaps they themselves have forgotten or the truth is too terrible to countenance. Many tales are told of genetic engineering conducted in the distant past, during the earliest history of Humanity. Their unique position in Human society gave them great power and leverage, allowing them to establish almost absolute control over trading and mercantile affairs throughout the galaxy, building an enormous power bloc which, though its strength has waxed and waned over the millennia, has never been broken. Today, the Navis Nobilite (as it is now known) thrives as a vital part of the Imperium and, through time, the Navigators have come to control the vast majority of commerce across the Imperium, ruthlessly exploiting their monopoly on long distance interstellar travel to make the largest families inconceivably wealthy. Supported by a complex network of fealties, oaths, tithes and contracts, the great families controlled the movement of almost all goods across the Imperium.
These powerful families divided into many individual Houses or Great Families. Each House is a large related family, but is also a literal house, a fortified mansion where the House leader, or Novator, lives together with his immediate kin and retainers. This mansion is regarded as the seat of the entire Great Family, even though it is only the hereditary ruling family that lives there. This centralisation of power serves two purposes; it provides a focus for the material power and wealth of the Great Family, but also serves to control the breeding and progression of the family genome. The Navigator-gene can only be preserved by intermarriage, as it is lost when a Navigator breeds with an ordinary human.
Then, as now, most people shunned Navigators. With their strange three-eyed appearance, few would have dealings with them, and many in positions of power were jealous of their privileged status. Superstition and fear surrounds them, as it does all other mutants.
The Navigator Houses
The most powerful of the Navigator houses have their Family House on Terra, in a vast district known as the Navigator's Quarter, a byzantine labyrinth of ornate buildings, decorated beyond any measure of taste. Every palace is huge and decorated with mighty murals and elaborately painted ceilings, the Navigator Lords competing with each other to create the most beautiful palaces, adorned with the greatest works of art in the galaxy. They have libraries containing millions of books, data crystals and scrolls, and own collections of sacred relics to match anything possessed by the Ecclesiarchy. They own menageries of rare beasts, and wine cellars replete with the products of a million worlds and live in obscene luxury and splendour.
An estate surrounds each palace, containing sculpted gardens and ornamental pleasure lakes filled with scented water. Beneath the palaces is a far darker world; the Vaults. These vast labyrinths stretch downwards towards the planetary core and are the sometime home to the strange mutated ancients of the Houses.
The most powerful Houses vie for the position of Paternova, the overall ruler of the Navigator House's, whose powerful influence extends even to the High Lords of Terra. It is every Navigator House's ambition to one day reach the position of Paternova, and take control of the great Navigator Palace on Terra. Lesser Navigator families owe fealty to larger houses, which in turn have their own alliances. These alliances form trading cartels, which compete for lucrative contracts with other trading cartels. The Merchant Fleets of the Imperium must constantly deal with these powerful cartels for the services of the Navigators. It is a strained relationship at best, and while open conflict is rare, it is not unknown.
More covert methods are often employed. An assassin's bullet to remove a troublesome Novator or his envoys, to be replaced by a more amenable family member, is an oft-used recourse. So high are the financial rewards and influence to be gained that assassination attempts are a common transaction between rival Navigator Houses. Open warfare, in a controlled fashion, is not unknown between the feuding houses, since all control vast wealth, large professional mercenary forces are paid huge amounts to serve the Navigator Houses. Some of these mercenary contracts date back thousands of years. The Navigators, paranoid of their rivals, are afraid to be seen as militarily weak, and thus they pay well for loyal service, and failing this, they trade in slaves or penitents and train their own soldiery within their huge private estates. Slave trading is a lucrative business and so long as taxes and tithes are paid, the Administratum turns a blind eye.
The Heirs Apparent
The most powerful Navigators in each of the Great Families are called Heirs Apparent, which signifies that they may one-day contend for the position of Paternova, the ruler of all the Navis Nobilite. The Paternova may come from any of the Great Families and from any social level within them. The Heirs Apparent are usually the oldest Navigators, although not all develop in this way and some Navigators live out their entire lives without undergoing major physical changes.
The Heirs Apparent are frequently bitter rivals who will sometimes go as far as to try to eliminate each other if they get the chance. This sometimes leads to protracted personal vendettas or bitter feuds between two Navigator Houses. The Adeptus Terra is fairly tolerant of minor skirmishing of this kind, though open hostilities between Houses are discouraged as much as possible, with the exception of Tradewars.
A Tradewar is a limited and strictly regimented form of warfare, formally declared between rival trading factions, which is permitted by the Administratum under the Navigator Conventions. The aim of the Convention is to reduce the overall damage to shipping and mercantile interests, as well as prevent rival factions from simply destroying one another. The rules of a Tradewar prescribe formal declarations of intent and restrict permissible targets. The Great Navigator Houses see Tradewar more as an extension of the customary means of competition between competing commercial interests, than as open warfare. During a Tradewar, forces directly under the control of the warring factions are allowed to raid each others' shipping, attack important mercantile operations or destroy equipment owned by the opposition. Employees and declared members of rival houses become fair game for assassination attempts or direct attack, but violence cannot extend beyond the direct opposition, so subsidiaries and lesser Houses allied to the warring factions are theoretically immune to the effects of a Tradewar, though they are often dragged into direct conflict. In practice, Tradewars rarely last very long as they are expensive in money and manpower, and the profits to be gained by wresting control of commercial contracts of a specific market or shipping routes does not often justify the expenditure. They also tend to produce bitter enmities between the rivals, as the fighting is invariably of a tawdry nature, leaving many scores to be settled at a later date.
The Paternova is the leader of all the Navigators and the most powerful of his kind. The Paternova may live for up to a thousand years, and when he dies, all the existing Heirs Apparent begin to change. They grow larger and stronger, and their mutations become even more pronounced, becoming able to survive in hard vacuum as well as underwater or in poisonous environments. Most importantly, they start to fight. They are drawn into combat with each other; building up to a pitch of aggression that eventually overrides all other considerations. As Heirs Apparent are killed, those who survive change even more until only one remains alive. It is this vastly changed and extremely powerful individual who becomes the new Paternova.
The Paternova lives in the Palace of the Navigators, which lies on Terra in the centre of the Navigator's Quarter. Following his ascension, the Paternova never leaves the palace, the existing staff, soldiery and other retainers of the palace replaced by those drawn from the Paternova's own House. The chief amongst his servants is the Paternoval Envoy, who becomes one of the High Lords of Terra and sits on the Senatorum Imperialis. The role of the Paternova is an obscure part of Navigator biology, although no-one doubts its importance. He is sometimes described as the guiding father whose powers transcend the Warp itself. During the interlude between the reign of one Paternova and another, all Navigators other than the Heirs Apparent, suffer a considerable reduction in their powers. Their ability to navigate the Warp is impaired, Warp journeys take longer, ships are unexpectedly lost, and younger Navigators may lose their abilities completely.
As soon as the new Paternova is installed, the Navigators' powers are restored, though not all are restored to the same degree. Navigators belonging to the same House as the Paternova find their abilities enhanced, as though their blood tie were enabling the Paternova to transmit his powers more effectively. Navigators belonging to the House of the old Paternova lose this benefit, and many Navigators suddenly find their powers greatly impaired.
Inquisitorial Purges and Pogroms
The Navigator Houses hold a unique position within the Imperium; they are not answerable to the authority of the Imperium, but tend to toe the Imperial line because of the mutual benefits each side receives. So powerful a force within the Imperium are the Great Navigator Houses, that they command a place within the Senate Imperialis. The Paternoval Envoy is the current ruler of the Navigator Houses' representative to the High Lords of Terra. Because of this power, the Imperium remains suspicious of the motives of the Great Navigator Houses. Prejudice still lurks against their mutated appearance and some whisper that the Navigators have been tainted by Chaos. All in all, the Navigators are tolerated only as a necessary evil.
The holy agents of the Inquisition keep a close eye on the Navigator Houses, ready to seize upon any indication that the Navigators have strayed beyond the already widened boundaries of tolerance. Whispers of dissent among the Great Houses are ruthlessly crushed by Inquisitorial purges against the offending Houses; goods and assets are seized, midnight raids on Navigator palaces are followed by arrests and a purging of those seen as tainted, their fate to be burnt as heretics or locked away in Inquisition torture chambers. The Navigators have come to fear the power of the Inquisition, but to offer resistance would bring the iron fist of Imperial justice down upon them and the freedoms they enjoy within the mercantile world would be lost.
Fear the Mutant
As well as their obvious mutation, a single dark eye in their forehead, other, lesser, mutations are not uncommon amongst Navigators. Many of the Navigator Houses have spent a vast amount of time in the Warp and, though they are exceptionally resistant to the powers of Chaos, the corrupting power of the Warp has taken its toll on the physical forms of the Navigators through the generations. Most of the families hide minor mutations, but the problem is accentuated by the intermarrying of the Great Houses to secure political allegiances and gain additional prestige. Over the millennia this stagnating gene-pool has created more cosmetic mutations: obesity or anorexia, bulbous facial features, large ears and withered limbs are all common amongst the nobility of the Navigators. More sinister mutations are hidden from view, the worst sufferers hiding within the privacy of the palaces, never to see the light of day, their hideous deformities hidden from the Imperium behind a mask of wealth and luxury. Many Navigator children are killed at birth, mutated beyond recognition, abominations even to their strange race.
Navigators in the 41st Millennium
The Navigator houses of the Navis Nobilite are amongst the most important individuals in the Imperium. They lease out their members to various institutions across the galaxy, either for currency or through ancient pacts and debts. These are always honoured and, in this respect, the Navigators are extremely honourable indeed, as to renege on them would be costly in financial terms as well as the accompanying loss of face.
Ships of the Imperial Navy and Merchant Fleets are always accompanied by a member of one of the noble houses of the Navis Nobilite, compelled by ancient and binding oaths to serve with the Tech-Priests for a set duration in return for the Tech-Priests' services. This is invariably seen as a serious chore for the Navigators in question who, unlike their Adeptus Mechanicus employers, appreciate the finer things in life.