The River

The River is a vast mystical current, a so-called liminal space "below" the perceptible world, belonging to the realm of soul magic. It is the place to which souls are automatically transported upon vacating their bodies (apopneumatism), with the exception of ghosts and revenants.

History

After the Resurrection, The Emperor and his Lyctors desperately needed to put space between themselves and the Resurrection Beasts that were depleting their numbers. The remaining seven of them sank into the River and fled forty billion light years to what would become known as the Mithraeum.

Many thousands of years later, Cassiopeia the First attempted to bait physical portions of a Resurrection Beast into the River directly, as opposed to fighting its soul via spirit projection. She survived for nearly seven minutes before being destroyed by the ghosts that reside in the River. The Beast emerged unscathed, twenty minutes later.

Composition

"Your mind you dug out of your meat, and you drove it downward—always downward, somehow—and pushed with your awareness until you felt underfoot the dagger-sharp rocks of that grey and unimaginable shore beneath that grey and unimaginable sky. Then a step into that icy water, and another, until you were waist-deep and might open your eyes."

Imagery

The River is not a physical river, but rather an intangible, or metaphysical, spirit-magic realm between the physical world and what comes after death. To Harrow, this appears a vast body of translucent, blood-coloured water--imagery that may be shared by other Lyctors given the propensity for river-based terminology. Harrow further describes its appearance as "filthy, rusty red, with a bloom like sewage," taste as "like effluent," and smell as "like blood." It does not appear to exhibit any particular magical properties, or to have any particular ambient temperature, being described at various times as ice-cold, tepid, and warm.

Layers

The River has considerable depth, sufficient to warrant its subdivision into four distinct layers—in descending order:

1. Epirhoic (EPPY-ro-ic): The epirhoic is the top layer, consisting of the River's surface and the shore. From "epi-" meaning "on top of"; "-rhoic" from the Greek "rhoe" meaning stream or flow.
2. Mesorhoic (MEE-so-ro-ic): The second, or alternatively the "middle" layer between the epirhoic and bathyrhoic layers. From the Greek "meso-", meaning "in the middle".
3. Bathyrhoic (BATH-ee-ro-ic): The bathyrhoic layer is the deepest that River-dwelling ghosts will usually venture. From "bathys", meaning "deep".
4. Barathron (ba-RA-thron): The lowest level of the River, hence its alternative description as the "Riverbed". The stoma are found here, along the bottom of the Riverbed. From Greek, meaning "a pit". Classically describes a location in Athens where criminals were sometimes thrown.

The Stoma

"'It is the mouth to Hell', said God."

The stoma are massive, mouth-shaped openings on the bottom of the River. They are described as being lined with enormous human teeth, each "six bodies high and two bodies wide". Normally closed, stoma are said to open in the presence of Resurrection Beasts, though the extent to which this is true is uncertain—a stoma is also seen to open in the presence of John Gaius. Upon opening, a large number of giant pink tentacles bearing resemblance to human tongues emerge and attempt to ensnare nearby objects. In the case of the battle between Augustine the First and John Gaius, the tentacles prioritized pulling in Gaius, but did not ignore the Lyctor. This suggests that the stoma (or unknown entities within) prioritize their targets, potentially based on levels of inherent thanergy.

Beyond the stoma is an unfathomable black void, a "genuinely chaotic space" in which the Emperor claims his power is "utterly meaningless". Nobody who has entered a stoma has ever reemerged. The Emperor and his Lyctors utilise the stoma to dispose of the souls of the Resurrection Beasts, presumably destroying them in the process.

River Travel

The Emperor and his Lyctors use the River to travel enormous distances at speeds in excess of the speed of light. This is made possible by the fact that the River occupies a space and time distinct from that of the normal universe; passing through it is (somewhat) akin to boring through a planet's core rather than travelling across its surface.

"Girls, imagine a rocky planet with a magma core beneath the mantle. Travelling overland from point to point might take a year. If you understood your journey and the relative spaces well enough, you could instead drop into the magma, which would carry you to your destination in an hour."

While travelling by River has distinct advantages over the more commonplace means of superluminal travel via stele—a stele must be inscribed with dead languages by Fifth adepts and continuously bathed in oxygenated blood, for example—in reality it is not practical for anyone other than Lyctors. For a normal necromancer, the River strips away their thanergy, thalergy, and soul in a matter of seconds. Lyctors, with a seemingly bottomless reserve of thanergy and thalergy, have the ability to survive in the current, but none have successfully done so for longer than seven minutes. The true danger to a Lyctor in the River is the horde of ravenous ghosts who reside there and attack without mercy.

The River Beyond

The River Beyond is a minority belief within the Empire of the Nine Houses that claims the River is actually a transitory realm, intended to bring souls to the real afterlife beyond. The belief in the River Beyond has largely died out, but some still believe in it, including Abigail Pent. Pent believed that something had gone wrong in the River, preventing it from serving its true purpose, though she had hope that the innocent souls of Jeannemary Chatur and Isaac Tettares would still be able to pass through safely.