The Navis Nobilite is the ancient confederation of noble houses from which the Imperium's Navigators are drawn, a hereditary aristocracy whose unique mutation makes interstellar travel possible. Set apart from ordinary humanity by both their power and their strangeness, these houses are among the oldest and most powerful dynasties in existence.
The gift they carry is the Navigator gene, which grants a third eye, the warp-eye, able to perceive the light of the Astronomican and to steer a vessel safely through the treacherous currents of warp travel. Because this ability cannot be taught or replicated, only inherited, the great houses guard their bloodlines jealously, arranging marriages and alliances across centuries to preserve and strengthen the gift.
Their indispensability grants the Navis Nobilite extraordinary privilege. No Imperial fleet, trade route, or crusade could function without them, and so they command wealth and influence that even the Adeptus Terra must respect. Yet they remain mutants, tolerated rather than embraced, their palatial households a world apart from the humanity they serve. Proud, insular, and riven by feuds between rival houses, the Navis Nobilite is a necessary aristocracy of outsiders upon whom the whole Imperium depends.