Warhammer 40k Lore for Beginners (Srtart with 40k)

The world of Warhammer 40k is vast and intricate. Jumping in at this point leaves us with so many questions it can be hard to know where to start. However, some great starting points still exist.

Learning Warhammer 40k is best done in three parts. The first one should be the basics of the universe, factions, and races. Then come a couple of universe-changing events. After that, the best way to learn more is by choosing a faction or event you like the most and diving into works tied to it.

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The Basics of the Warhammer 40k Universe

The universe of Warhammer 40k is one of constant war, conflict, and strife. The setting has been the biggest inspiration for the grimdark subgenre. Warhammer 40k is often used as the poster child of said subgenre, containing all the important traits of one. Amorality is a key trait, as each faction in the universe is deeply flawed.

In 40k, there is a significant overlap between science fiction and fantasy. Demons are real, and so is magic, but both come from an actual place one can visit if only to be corrupted or slain. 

The technology works partially on old-fashioned engineering principles while also being supported by prayers to the more potent beings in the universe.

Psykers are the most interesting part of the setting. These individuals are gifted with the ability to control psychic powers at will. Their position in the universe is constantly shifting, with most human Psykers being treated as criminals for their powers.

The Factions of the 41st Millennium

There have been hundreds of factions within the thousands of pages of content written since the first book back in 1987. Each with its agendas and focal figures, the factions are the source of endless intrigue in the setting.

Generally, factions can be split by races of the Warhammer 40k universe and then again on a race-by-race basis. Necrons, for example, have dynasties that act as separate factions with their own motives, leaders, and goals.

We can more concisely split the factions of the 41st millennium into three groups: 

  • Imperium of Man 
  • Chaos 
  • Xenos 

The most frequent one that gets the spotlight in the setting is Imperium of Man, due to being a key human faction, but each grouping has something to offer.

The Beginning of The Warhammer 40k Universe and the Lore

To get started with Warhammer 40k lore, it’s important to understand the beginning of the universe.

It all started with the C’tan, powerful beings of energy who existed near stars. The Old Ones, an advanced reptilian race, created the Webway, a way to move through space faster than light without entering the dangerous Warp. The Old Ones ruled the galaxy until they encountered the Necrontyr, a fragile race seeking immortality.

The War In Heaven

The Necrontyr and the C’tan formed an alliance to defeat the Old Ones in a war called The War in Heaven. The C’tan betrayed the Necrontyr by turning them into the Necrons, beings of metal, and the Necrons defeated the Old Ones. The Necrons then destroyed the C’tan and went into hibernation until they could overpower their enemies in the future.

After the War in Heaven, the Aeldari and the Krork were left behind as remnants of the Old Ones’ creations. The Aeldari were highly psychic beings, and their emotions had a strong presence in the Warp. They used the Webway to create their own civilization, but their decadent ways eventually led to the birth of Slaanesh, a Chaos God. The birth of Slaanesh caused the fall of the Aeldari civilization, and the remaining Aeldari became known as the Eldar.

Meanwhile, the Krork continued to evolve and become stronger, ultimately transforming into the Orks, a race of highly aggressive and warlike beings.

The Imperium of Man was formed in the wake of these events, when humans emerged as a dominant species. The Emperor of Mankind united the human race and created the Space Marines, genetically enhanced soldiers, to protect humanity from threats such as the Orks, the Chaos Gods, and the Necrons, who eventually reawakened from their long hibernation.

The Imperium of Man faces numerous threats from within and without, including the Chaos Space Marines, who worship the Chaos Gods and seek to destroy the Imperium; the Tyranids, a race of highly evolved and adaptable beings who seek to consume all life in the galaxy; and the Tau Empire, a technologically advanced race with a powerful sense of unity and purpose.

Understanding the history and factions of the Warhammer 40k universe is key to enjoying and participating in the tabletop game and its associated lore.

The Aeldari, a powerful psychic race, dominated the galaxy for millions of years. However, their civilization fell into ruin after the birth of the Chaos God Slaanesh.

Humanity rose to power around 40,000 years ago in the Age of Terra, and the Emperor of Mankind, who had lived for thousands of years, emerged from the shadows to unite humanity under his rule. During the Dark Age of Technology, humanity made great strides in technological advancement, but the emergence of Chaos Gods like Khorne, Tzeentch, and Nurgle made travel through the Warp difficult.

The important events that formed the 40k Universe
(Rise Of humanity, Age of Strife, Great Crusade, and Horus Heresy)

Psyker navigators became essential for travel, and for 10,000 years, humans colonized other planets and grew technologically.

However, in the 25th Millennium, the Age of Strife began, halting technological advancement and leading to the rise of the Imperium of Man.

Age of Strife

During the Age of Strife, humanity’s progress came to a halt as their civilization crumbled under civil wars, disease, and other catastrophes.

The warp became even more unstable, and the chaos gods’ influence grew stronger, leading to the birth of countless demons.

It was during this time that the Emperor of Mankind revealed himself and began his conquest to reunite humanity and bring order to the galaxy.

He created genetically-engineered super soldiers known as Space Marines, and the Imperial Guard to serve as his armies. He also built the Imperial Palace on Terra as his base of operations.

The Great Crusade and the Horus Heresy

There are two very important events in the history of the Warhammer 40k universe. The first one is the Great Crusade which marked five thousand years of humanity spreading across the stars and prospering. 

The crusade was led by the Emperor himself while he was still fully alive, and was a great success. 

Eventually, the Emperor retreated to Terra in order to finalize a secret project for the future of mankind while leaving his son Horus as the head of the Great Crusade.

Horus Heresy was motivated by this retreat of the Emperor. The lack of transparency in the plans as well as the appointment of civilian political figures, made Horus distrustful. 

He spread this distrust among other Primarchs, eventually leading to Horus and eight others rebelling against the Emperor. This event plunged the Imperium of Man into a dark state it has been in for 10,000 years, with most primarchs dead, missing, or turned into daemon princes. 

It’s a heavily recommended starting event for beginners interested in the Warhammer 40k lore.

The Great Crusade

The Emperor’s crusade lasted for centuries, and he was able to defeat many of his enemies, including the Orks, Eldar, and Chaos forces.

However, his ultimate goal was to find and unite all of the scattered human colonies, so he launched the Great Crusade to conquer the galaxy and bring them all under his rule.

The Great Crusade lasted for more than two hundred years, and the Emperor and his armies were able to conquer many worlds and defeat many enemies. But the Emperor’s hubris and arrogance led to his downfall.

He was betrayed by one of his own sons, Horus, who had been corrupted by the Chaos Gods, leading to a catastrophic civil war known as the Horus Heresy.

The Horus Heresy

The Horus Heresy lasted for ten years and nearly destroyed the Imperium. Many Space Marine Legions turned against the Emperor and joined Horus, leading to a brutal conflict that saw entire planets destroyed and billions of lives lost.

In the end, the Emperor and his loyalists were able to defeat Horus, but the cost was high, as the Emperor was mortally wounded and forced to enter the Golden Throne to keep the Imperium alive.

Now, ten thousand years later, the Imperium is a shadow of its former self, and humanity is fighting a losing battle against countless enemies, both from within and without.

The Imperium is beset by Chaos forces, alien threats, and even its own citizens, who sometimes turn against it in rebellion. Yet, there is still hope that the Emperor will one day return and lead humanity to victory once again.

The Emperor and the Imperium of Man

Imperium of Man is a massive faction that spans thousands of planets, each with its own purpose. However, the Imperium is quite an oppressive place to live in, with a strict focus on laws and survival. It’s more of an exceptionally big ant colony than a functional empire.

Imperium of Man includes Adeptus Astartes, Astra Militarum, Inquisition, and other adjacent factions. They all contribute to fighting against the Chaos and otherworldly beings in one way or another.

The Emperor

The Emperor himself is currently a corpse on a golden throne that acts as “life” support. Although that may seem unimpressive for a ruler of such a massive faction, it’s anything but. Even as a husk, the Emperor supports his subjects through psychic powers and is said to keep out chaotic entities of the warp from breaking into our world with his mind alone.

The Emperor is among the most powerful psychic beings in the galaxy and an immortal who has been around since humans were even younger of a race. He led humanity far across the stars until he was put in his current state during an event known as Horus Heresy.

Chaos and the Forces of the Warp

The greatest enemy of the entire universe is Chaos. 

In Warhammer 40k Chaos is a very complex concept, but the generalization of it would be as psychic and spiritual energy that forms an alternate dimension called Immaterium. 

Chaos, as a faction, refers to anything created within this dimension. It also extends to any of its worshippers in either Immaterium or the material world. 

There are four Chaos Gods, each with a different domain:


Khorne is the most straightforward god. A god of war, murder, and violent death. 

With the constant war and bloodshed, Khorne is currently the most powerful Chaos God. Khorne hates any form of magic and is more than keen on magi having their blood spilled in his name. 

His most devout followers are furious berserkers who charge into combat with little time for tactics.


Nurgle is the next Chaos God, one of disease and decay. 

His worshippers spread diseases, gestate them, and even make new ones. They are often horribly deformed and swollen with all sorts of disgusting symptoms of the disease. The victims of disease sometimes turn into worshipers as a way to gain respite from their horrible diseases.


Slaanesh is the next in line, the god of pleasure and pain. 

This chaos god is constantly seen as one of self-indulgence. While Slaanesh is the youngest of the four, their growth in power is exponentially faster due to the nature of all sentient beings. 

Humans and Aeldari are the most responsible for this power increase.


Tzeentch is the last of the four, the god of change and knowledge. 

Sorcerers and Psykers most commonly worship him, but anybody willing to make a change will find themselves as a potential ally to this Chaos God. Tzeentch’s worshippers spark revolutions, change the established rules, strive to break apart anything stagnant and make it change.

The entities also form a pantheon named Chaos Undivided, which has its separate followers.

Worshippers of Chaos Undivided see each entity as part of one whole. This allows them to approach every concern through the lens of one god, all of them, or none. 

Additionally, it allows the Chaos Undivided worshippers to spark alliances between any followers of Chaos Gods, even if they usually hate each other.

The Races of Warhammer 40k

In this vast universe, one can encounter many different species. Their culture and goals are unique, as well as their presence in the galaxy-wide wars.

Imperium of Man

Humans exclusively inhabit the Imperium of Man. 

For thousands of years, the Imperium has waged war against any alien species they encounter. Their huge expansion and haphazard inhabiting of various worlds have also led to some of the humans evolving unique traits for their worlds. 

These humans are labeled under ‘abhumans’ and usually differ greatly from regular ones. The known species of abhumans involve ratlings, squats, and ogryn. The Imperium of Man strives to recover its glory.


With so much negative energy throughout the universe, it makes sense Chaos itself would grow. 

As noted before, Chaos is a metaphysical force, and the place it most prominently occupies is the Immaterium. However, there are still species within it. 

Chaos contains millions of mutants, demons, warp predators, and even races from the material realm that decide to cross into it.


Eldar or Aeldari are an old race that fell from grace. 

These former rulers of the universe now live in ever-dwindling numbers no matter whether they dwell on giant psychic ships Craftworld or within an interdimensional labyrinth. The first are strictly traditional Asuryani, and the latter are exceptionally hedonistic Drukhari. 

Eldar struggles to survive as cosmic threats keep threatening the ruins of their civilization.


Violent, simple, and numerous greenskins of the Warhammer 40k universe. 

Their passive psychic powers affect reality, allowing these halfwit brutes to succeed more than one would expect. Even if you take out a whole warband of Orks, another will sprout from their quickly gestating spores. 

In the 40k universe, Orks are the simplest of the races, with their only goal being to fight. If they can’t find somebody to fight they will fight themselves, spreading their spores and birthing more Orks.


Space skeletons with inspirations taken straight out of a book on Egyptology. 

Necrons were once a race called Necrontyr that lived on a planet filled with horrible radiation that ruined the entire race’s society which always lived in anticipation of death.

They then managed to put star gods named C’tan into metal shells, later being turned into those same metal shells through the trickery and greed of C’tan. Now Necrons wake throughout the universe, annihilating life and rebuilding their dynasties.


Alien hiveminds from out of the Milky Way galaxy, Tyranids, are dangerous and impossible to reason with. 

Tyranids replace technology with genetic mutations. These mutations quickly assimilate the perks of their foes into Tyranids’ own ranks. The motive of these aliens is to feed on all that lives. 

Tyranids also use human agents to grow their presence on planets. These Genestealer Cults will prepare the planet for invasion and eventually be eaten themselves.

T’au Empire

The Milky Way galaxy’s youngest and most naive race, T’au, are blue humanoids with some potent tech. 

T’au are subservient to Ethereals, who have massive political power and seem to have elevated T’auT’au from a primitive state of being.

Ethereals maintain their power through the use of plentiful forms of mind-altering procedures, as well as through the caste system. Additionally, T’au are known to incorporate other alien species into their ranks along with their massive battlesuits. 

T’au wish to spread the message of unity and the Greater Good, although with a healthy amount of questionable techniques.

Daemons of Chaos

As mentioned above, the Daemons of Chaos live in the Immaterium. They differ in appearance based on the Chaos God they are associated with and even then, daemons can get quite diverse. 

Daemons are very simple in their behavior, unless directed by greater daemons or other more influential acolytes of Chaos.


Xenos is a term used by the Imperium of Man for any alien species. 

While we’ve named some of the biggest and most intelligent Xenos races in the universe, there are countless others. 

Thousands of them were encountered during humanity’s initial exploration of the cosmos, and many were killed during it. Of course, a galaxy is a massive place, so there’re plenty of different ones still about.

The Role of the Space Marines in the Imperium

Each Space Marine is a magnificent feat of science and intense training alike. 

Space Marines were created by the Emperor of Mankind himself to be the most loyal and powerful soldiers that will stand at his side. Space Marines are the greatest bulwark against humanity’s enemies.

Before the Horus Heresy, among them were 20 Primarchs, a special type of genetically-engineered men who were dubbed sons of the Emperor and each given a chapter of Space Marines to lead.

The Dark Age of Technology

Among the many ages of humanity, the Dark Age of Technology was the most technologically advanced era of humanity. 

The Dark Age of Technology birthed many interstellar technologies, navigation throughout space, and powerful military technology.

The dark in the name comes from the current Imperium regarding technological advancements such as these as heretical. The era, in their eyes, is a shining example of humanity being led astray by technology, worshiping it as its god.

The Current State of the 41st Millennium

While the metaplot of Warhammer 40k has been stagnant for a while, the release of the 9th edition has provided some important shake-ups. The biggest was the recovery of one of the loyalist primarchs, Roboute Guilliman.

He is the leader of the Ultramarine Legions and the more politically savvy of his brothers. 

His return alone signifies extreme changes to the world of Warhammer 40k and leaves the community at large waiting for the massive changes that this will cause.

Additionally, the primarch brought with him a new type of Space Marine. Primaris Space Marines are even stronger than regular ones. 

Primaris have proven their prowess but still remain a divisive topic in the Imperium.

Important Planets and Locations in Warhammer 40k

  • Cadia: now destroyed planet of Imperial Guardsmen
  • Ultramar: Homeworld of one of the best known Space Marine chapters, Ultramarines
  • Immaterium: a dimension separate from the material world, it is filled with horrors beyond comprehension
  • Terra: the Earth of Warhammer 40k, a planet-wide fortress that houses the Emperor
  • Eye of Terror: a tear in reality that combines Immaterium and the regular world, created from the psychic shock of Slaanesh being born
  • Mars: The homeworld of Mechanicus and the planet of many secrets. It was the first human colony created thousands of years ago.

The Future of the Warhammer 40k Universe: An Overview of Upcoming Events

There are plentiful things that could happen in the future of Warhammer 40k. 

Necrons seem to grow in power with each passing day, the return of Guilliman may potentially change the Imperium at its core, Tyranids are still a lurking threat, and horrors of Chaos now have even more targets.

A new faction in the form of Leagues of Votann, short abhumans who are basically space dwarves, also raises a couple of questions. 

Whether they play a bigger part in the grand scheme of things is yet to be seen.

Chaos itself seems to have a civil war brewing, which is a massive worry. As a result, there are new lines being drawn in the sand while the potential for stories only grows.


Warhammer 40k lore should be easier to parse with these starting points established. 

They cover most of the important details one needs to understand the basics of the universe. If you wish to learn more, pick a starting point and go from there. Each faction, event, or concept will sprout dozens of new threads to follow until you’ve finally satisfied your curiosity.