The Shadow in the Warp is a psychic phenomenon generated by the Tyranid Hive Mind that blocks all connections to the Immaterium in the local space around a hive fleet, making psychic communications or the manifestation of psychic abilities extremely difficult. This unique phenomenon greatly affects astropaths, Navigators and psychic species, such as the Aeldari.
The coming of a Tyranid hive fleet is preceded by a smothering psychic signal similar to white noise that envelops entire star systems and disrupts all forms of Warp travel and communication.
Swallowed up by psychic-static, whole worlds suddenly go deathly silent, giving no clues as to what is unfolding on the surface below, or of what terrors are about to befall. This is the Shadow in the Warp, and it heralds imminent invasion and horror.
It is unknown if the Shadow in the Warp is created deliberately by the hive fleets, or if it is simply a by-product of the Hive Mind's innate synaptic control of the species' bioforms. In any case, the Shadow in the Warp creates fear and panic wherever it falls, instilling a pervasive dread into the minds of a prey worlds' defenders, plunging entire planets into misery and despair.
For highly psychic races, such as the Aeldari, or for luckless psykers of any intelligent race caught within this enervating effect, the malaise is magnified tenfold.
Should a psyker attempt to use their otherworldly abilities, the cerebral cacophony worsens even further; the psychic sound of a billion alien thoughts scratch at their mind, and unless they are particularly strong-willed they will be pitched into an insanity where they will repeatedly utter phrases in a tongue too alien to properly pronounce.
For races such as Humanity, whose means of interstellar communication and travel rely upon highly specialised psykers such as astropaths and Navigators, the Shadow in the Warp is one of the deadliest facets of the Tyranid menace.
Bereft of their means to call for reinforcements or safely navigate surrounding space, worlds of the Imperium of Man under assault by Tyranids are easily isolated from the wider galaxy.
This means that, by the time the Shadow in the Warp falls, it is already too late; these beleaguered planets are effectively on their own. They must fend for themselves and face the Tyranid swarm with the weapons they have to hand, or die in the attempt.
Sources[]
- Codex: Tyranids (4th Edition), pg. 31
- Deathwatch: The Achilus Assault (RPG), pg. 45
- Warhammer 40,000: Conquest Collectible Card Game (Picture)