Overview
The Eye of Terror is a wound where realspace and the immaterium trespass upon one another with obscene familiarity. It is mapped as a region, feared as a door, and treated by sane navigators as an argument against curiosity.
Worlds within and near it obey laws that Imperial record-keepers can describe only by failure. Time, distance, loyalty, and flesh become unreliable categories.
History
The Eye's existence shaped Imperial strategy across the north-west for millennia. Around it grew quarantine routes, fortress systems, inquisitorial watch patterns, and the grim confidence that disaster could be contained if the gate held.
That confidence was always a prayer disguised as policy.
Military significance
The Eye is not an army, but it produces armies, raids, cults, daemon hosts, renegade fleets, and strategic nightmares. It forced Cadia and the surrounding bastion worlds into permanent watchfulness.
Its military significance is negative and absolute: every Imperial resource spent containing it is a resource not spent elsewhere, and every lapse becomes an invasion corridor.
M41 and M42 status
Immense warp rift and source of repeated incursions.
M41 status: The Eye remains the principal Obscurus warp hazard and the source of repeated incursions through and around the Cadian Gate.
One end of the wider galactic wound.
M42 status: After the opening of the Great Rift, the Eye is no longer an isolated horror. It is part of a greater galactic wound, and old containment language is now mostly memorial.
Timeline
Obscurus watch stations renew long-range quarantine patterns around the rift.
Navigator houses revise hazard tariffs for Eye-adjacent routes.
Raid vectors from the Eye force Cadian Gate reinforcements.
Inquisitorial interdiction lists expand across surrounding systems.
The region erupts into a crisis that redraws Imperial assumptions.
Navigators classify the Eye as part of a larger Rift-era hazard system.
Cartographic positions and several administrative details are intentionally approximate where published Warhammer sources conflict or provide no canonical coordinate system.