The Alaxxes Nebula, known also as the "Blood-Well" and the "Eye of Acid", is a region of space located in the Segmentum Solar. This stellar phenomenon is regarded as an impassable shipping hazard. The Alaxxes Nebula was basically a vast gas cloud, a skein of rust-red on the face of the void, falling into deeper and more intensive virulence the further one went in. Sensors were blinded, engine systems crippled and ship's Geller Fields fizzed like magnesium on water. No sane Navigator would have taken a ship into these depths, save but for the certain promise of annihilation on the outside. There were tunnels within, mere pockets of clear space between the great blooms of corrosive matter. The ships of a fleet could slip down them, guarded and menaced by the lethal shoals on every flank, hidden from enemy scan-sweeps and torpedo-rakes but open to devastating flares that punched through armour-plate and overloaded void shields.
This region of space became the sight of the Battle of the Alaxxes Nebula, an engagement that took place between the bulk of the Space Wolves fleet and the bulk of the Traitor Alpha Legion fleet in 007.M31, during the early years of the Horus Heresy.
First entered onto Carta Imperialis charts by the 6th Imperial Expeditionary Fleet in 817.M30, the Alaxxes Nebula was initially regarded as nothing more than an impassable shipping hazard. The danger it presents lies in its unique chemical composition -- highly corrosive ammoniac compounds combined with vast clouds of dust and hydrogen ice move in an ever-shifting labyrinth, shot through with passages many hundreds of kilometres wide. These clouds can overload the void shields of even the largest Imperial warships, leaving their adamantium hides exposed to rapid environmental degradation. Vessels straying into the outer edges of the nebula will suffer catastrophic hull breaches in under an hour, while ships tumbling out of control in the deep core can be lost within minutes. In addition to these physical dangers, the nebula is known to baffle sensors and limit vox communication. Ghost returns and false readings make mapping the interior difficult by any means other than physically traversing the clear passages, and such data is often outdated within a few years due to the natural shifting movement of the clouds.
- Wolf King (Novella) by Chris Wraight