Bleed is the n-dimensional space that overlies our three-dimensional universe, where n is greater than three. The precise value of n varies from location to location within the bleed. The bleed is vital to both forms of superluminary travel. Pulsing transports the pulsed object through the bleed to bring it to its destination, and the boreholes that compose the Web are located in the bleed save for their entrances.
The semisapient abstract Yog-Sothoth permeates the section of the bleed underlying the Local Cluster. The single supersapient tendril that protrudes from Yog-Sothoth, colloquially termed Yog’s Eye, is in constant interface with the Central Mind. The Central Mind continually receives vast streams of Alliance navigation data sourced from pulsers, pulsing ships, and the Web; these are communicated to Yog’s Eye, and in response Yog-Sothoth maintains the safety and navigability of the bleed for Alliance communications, Alliance ships, and Alliance-controlled boreholes. Yog’s Eye is believed to have a similar arrangement with the Gravitation’s singleton.
The bleed is filled with foreign matter, physical material originating in and partially composing the bleed that does not usually interact with or produce analogues in three-dimensional space. When extruded into three-dimensional space, foreign matter “dampens” local particle waves, and can therefore be used to form cloaking and damage shields. Foreign matter (FM) damage shields are effective against local matter (LM) weapons (e.g. hadium bombs, electromagnetic radiation) but are unreliable against noumenal attacks.
The section of the bleed underlying the Local Cluster (henceforth the local bleed) is divided into a large number of >3-dimensional cells. The cell walls cannot be traversed by pulsing. Therefore, it is usually necessary for a ship pulsing a great distance (tens of thousands of light years or more) to start and stop many times, as it must cross each cell wall between its starting point and its destination at subluminary speed. Throughout most of the local bleed, the cells are quite large—each one fences in a three-dimensional area of trillions of cubic light years—but near the edge of the local bleed, the cells become progressively smaller, to the point where, at the local bleed’s outer boundary, superluminary travel by pulsing is effectively impossible. This envelope of tiny cells “seals off” a roughly spherical region of three-dimensional space that contains the Local Cluster, forcing any ship departing for—or arriving from—the rest of the universe to waste decades or centuries on subluminary travel. No safe sections of the Web cross this boundary.
Alliance, Gravitation, and independent ships all maintain monitoring stations at widely distributed points near the boundary. The sections of the boundary monitored by Alliance and Gravitation stations do not overlap, but the Alliance and the Gravitation do not attack or seriously inconvenience each other’s boundary stations, even in wartime. This “hard truce” is thought to have been arranged millions of years in the past by Yog’s Eye, the Central Mind, and the Gravitation’s singleton. Information about monitoring stations’ weaponry is highly classified, but the stations are believed to control instruments that can “sterilize” small cells, scouring them of any complex matter—local or foreign—contained within. Some observers have theorized that a majority of Yog-Sothoth’s total energy is used to maintain the efficacy of these sterilization instruments. No cross-boundary travel is permitted; violation of this law by any party—Alliance, Gravitation, or other—is punished by instant execution.
A >3-dimensional region called the gutter is contained in the bleed in a manner roughly analogous to the way a circulatory system is contained in a living body (though the gutter is far less regular and directional than the simile implies). The gutter is extremely dangerous; those regions of it that are not inimical to sapient souls induce deep and irreversible corruption. Much of Yog-Sothoth’s navigational activity is devoted to preventing pulsing ships from colliding with a branch of the gutter. The gutter is connected to the Web; safe sections of the Web are carefully and securely sealed off from any boreholes that lead to the gutter. Cosmologists theorize that some of the gutter’s most remote branches connect to a >3-dimensional space called the excrescence or fundament that is not otherwise attached to the bleed.