"The greatest gift Mankind is blessed with is an inability to conceive of its true place in the universe—that of a pitiable shred of matter lost in an endless sea of crushing darkness—a gift without which the entire species would have slit its collective throat at birth."
- —The Arch-Heretic Elak Sarda
The Well of Night represents the point at which Imperial military forces reentered the region from the Calixis Sector half a galaxy away.
Since the start of the Achilus Crusade, the Well of Night and the Warp Gatehave been surrounded and guarded by the ring of Imperial outposts, void defence stations and Fortress Worlds known as the Iron Collar.
An immense swathe of chill nothingness devoid of stars or worlds, the Well of Night is empty wastes broken only by drifting invisible dust clouds of particulates that can shred hull armour as surely as a missile salvo and deadly null-energy reefs that can leave a starship floundering and powerless before the merciless cold void. At the heart of this killing darkness, seemingly static and unmoving, stands a terminus of the Jericho-Maw Warp Gate.
Since the Warp Gate's discovery, several attempts have been made by the Imperium to fashion a permanent base in proximity to the Jericho aperture. This has met with repeated failure, both due to the transitory perils of the Well of Night itself and the infrequent but deadly gravitic distortions and energy waves periodically emitted by the gate.
As a compromise, the Adeptus Mechanicus maintains a warship, usually of no less than cruiser tonnage, on station near the gate aperture to monitor it and serve as a relay point for voidships transiting through. Although the nominal tenure for these monitoring ships is ten solar months, it is rumoured in Imperial Navy circles that no single vessel during the last Terran decade has lasted more than seven months before having to send for relief and quit its post thanks to hull degradation and mounting damage.
Suffice it to say, once they have passed through the Warp Gate, voidships seldom tarry long in the Well of Night before engaging their Warp-Drives and travelling on to their selected destination in the Reach.
- Deathwatch: Core Rulebook (RPG), pg. 327
- Deathwatch: The Achilus Assault (RPG), pg. 102