The Immaterium

A Realm Beyond Reality

The Immaterium is a dimension existing beside the material universe.

It is commonly called the Warp.

Unlike realspace, the Warp does not follow ordinary laws of distance, time, matter, or cause. Thoughts may take shape. Memories may become places. Fear may draw predators. A moment may feel like an eternity, while centuries pass unnoticed elsewhere.

The Warp is not simply empty space used by ships.

It is an ocean of psychic energy shaped by living minds.

Human civilization depends upon it for travel and communication, yet every use risks contact with forces capable of altering reality.

Thought and Emotion Made Manifest

The emotions of living beings leave impressions within the Warp.

Fear, anger, hope, ambition, grief, devotion, desire, and violence all contribute to its currents.

A single emotion may leave only a faint trace.

The emotions of entire populations, armies, civilizations, or species can create powerful disturbances.

Places marked by massacre, worship, despair, or psychic activity may develop a lasting connection to the Warp.

This is why battlefields, shrines, execution grounds, and ancient ruins may feel different even when no visible danger remains.

The Warp remembers in ways mortals do not fully understand.

The Warp and Realspace

The boundary between realspace and the Warp is not equally strong everywhere.

In stable regions, the two remain separated.

In damaged or corrupted places, Warp energy may leak into reality.

Possible effects include:

• Altered gravity

• Distorted distances

• Repeated moments

• Unnatural weather

• Psychic voices

• Objects moving without cause

• Machinery behaving impossibly

• Shared dreams

• Mutations

• Daemonic manifestations

• Buildings changing shape

• Memories becoming unreliable

A Warp breach may begin as a small disturbance and grow into a threat capable of consuming a settlement or planet.

Closing such a breach may require psychic strength, sacred rites, technological intervention, destruction of a summoning site, or elimination of the force sustaining it.

Currents and Tides

The Warp contains currents that Navigators and psykers describe as tides, rivers, storms, reefs, and whirlpools.

These terms are metaphors for forces that cannot be understood through ordinary geography.

A stable current may allow reliable travel between systems.

A shifting tide may delay a fleet or throw it off course.

A violent storm may isolate entire regions, corrupt communications, or make travel impossible.

Warp routes can change because of:

• Mass death

• Psychic rituals

• Daemonic activity

• Powerful emotions

• Ancient devices

• Chaos influence

• Celestial events

• Unknown xenos technology

Controlling or understanding a stable route can be as valuable as possessing a world.

Warp Storms

Warp storms are regions of violent psychic instability.

They may block travel, distort messages, damage ships, and weaken the boundary between the Warp and reality.

A storm can surround one planet or engulf an entire region.

Worlds trapped behind a storm may become isolated for years or centuries.

During such isolation:

• Governments collapse

• Local religions change

• Technology deteriorates

• Cults spread

• Mutations increase

• New factions rise

• Old Imperial loyalties fade

When the storm ends, outside authorities may discover societies they no longer recognize.

The Eye of Terror is one of the galaxy’s greatest Warp disturbances.

Warp Rifts

A Warp rift is a direct wound between the Immaterium and realspace.

Rifts may be created by catastrophic psychic events, sorcery, ancient machinery, mass sacrifice, damaged pylons, or forces no mortal fully understands.

Near a rift, reality becomes unreliable.

Daemons may manifest more easily. Psykers may become stronger and less stable. Time may fracture. Mutations may accelerate. Ordinary people may experience visions, compulsions, or shared nightmares.

A small rift can become the center of a dungeon, investigation, siege, or campaign arc.

A major rift can reshape entire regions of the galaxy.

Daemons and Warp Entities

Daemons are beings formed from Warp energy.

Many are associated with the Ruinous Powers, though not every strange entity encountered in the Warp is easily classified.

Daemons do not possess permanent physical bodies in the same way mortal creatures do.

To enter realspace, they may require:

• Summoning

• Possession

• A Warp breach

• A corrupted relic

• A weakened Gellar field

• A powerful psyker

• Mass fear or violence

• Ground already marked by Chaos

A daemon’s form may reflect its patron, purpose, the emotions surrounding its arrival, or the mind of the person witnessing it.

Destroying its physical form may banish it rather than kill it permanently.

Psychic Power

Psykers draw upon the Warp to alter reality.

They may project force, read thoughts, see possible futures, manipulate matter, summon flame, shield allies, or communicate across impossible distances.

Every use creates risk.

A psyker may lose control, attract Warp entities, suffer injury, cause mutation, or allow something else to act through them.

Training, discipline, protective rituals, focus devices, and experience reduce these dangers but do not remove them.

Psychic powers may use D&D spell mechanics, including spell levels, concentration, saving throws, ranges, and durations.

The mechanics remain familiar.

The source remains the Warp.

Sorcery

Sorcery is the deliberate use of rituals, symbols, bargains, sacrifice, and forbidden knowledge to manipulate the Warp.

A sorcerer may also be a psyker, but psychic talent is not always the only requirement.

Sorcery may involve:

• True names

• Daemonic pacts

• Ritual circles

• Sacrifices

• Relics

• Astrological timing

• Enchanted weapons

• Corrupted machinery

• Forbidden texts

• Collective chanting

Sorcery can allow mortals to produce effects beyond their natural ability.

It can also attract entities that understand the ritual better than the person performing it.

Faith and Belief

Strong belief can affect the Warp.

The devotion of countless Imperial citizens may strengthen miracles, saints, sacred relics, and acts of faith.

Ork belief contributes to the strange psychic force surrounding a Waaagh!.

Aeldari traditions deliberately control emotion to reduce dangerous psychic consequences.

Chaos cults use devotion, fear, and sacrifice to weaken reality.

This does not mean every belief immediately becomes true.

The Warp magnifies emotion and symbolism, but its effects are inconsistent, dangerous, and influenced by powerful entities.

A miracle may be genuine without being predictable.

Dreams and Visions

The Warp touches mortal minds through dreams, instincts, visions, and unexplained memories.

A vision may reveal:

• A possible future

• A distant event

• A daemonic lie

• A symbolic warning

• Another person’s memory

• A psychic echo

• A manipulated prophecy

• An event that will never happen

Visions should rarely be treated as exact instructions.

They are strongest when they provide clues, choices, and uncertainty.

A true vision may still be misunderstood.

A false one may contain enough truth to remain convincing.

Corruption

Warp exposure can alter mind, body, and spirit.

Corruption may develop through:

• Repeated psychic contact

• Daemonic bargains

• Unprotected travel

• Chaos relics

• Warp-tainted locations

• Possession

• Sorcery

• Mutation

• Dependence on forbidden power

Signs may include nightmares, compulsions, altered senses, physical changes, strange luck, emotional instability, or attraction to certain symbols.

Not all Warp exposure leads to Chaos worship.

A survivor may remain loyal while carrying scars, mutations, or psychic sensitivity.

Franz should present corruption as a process involving warning signs and consequences rather than an unexplained punishment.

Mutation

Warp energy can alter living bodies.

Mutations may be minor, useful, harmful, unstable, or symbolic.

Examples include:

• Changed eyes

• Additional limbs

• Unnatural resilience

• Altered voice

• Psychic sensitivity

• Hardened skin

• Shifting features

• Unusual strength

• Unstable growth

• Traits reflecting a patron or emotion

Some mutations result from ordinary environmental causes rather than the Warp.

Within the campaign, the true origin should be known even when characters or authorities misunderstand it.

Nulls and Psychic Absence

Some rare individuals possess little or no presence within the Warp.

These people are often called blanks, nulls, or pariahs.

Their presence may suppress psychic power, weaken daemons, disrupt sorcery, and cause discomfort in ordinary people.

Many are instinctively disliked because others feel something is missing around them.

Nulls may serve the Inquisition, specialized Imperial organizations, prisons, or anti-psyker units.

Their abilities should be powerful but limited enough to remain compatible with party play.

The Immaterium in Play

The Warp should create danger, mystery, and possibility.

It may serve as:

• A source of psychic power

• A travel hazard

• A dungeon environment

• A cause of mutation

• A path for daemonic invasion

• A source of prophecy

• A corruption mechanic

• A battlefield complication

• A mystery behind altered reality

• A weapon used by factions

Warp events should have rules, clues, and consequences even when their full nature remains unknown.

Players should be able to investigate disturbances, identify patterns, make protective preparations, and choose whether forbidden power is worth the risk.

The Warp is not random magic.

It is a reflection of mortal existence made vast, hungry, and dangerously real.