A deep, deep dive into what the lore says about multiversal nature of the Warp, part 1: Recent lore (with many, many quotes)

TLDR: This is a long one (because there is so much source material to survey), covering tonnes of quotes from the lore which showcase that the notion of a multiverse is present in each of the 40k and Age of Sigmar lores, but that both settings are stated to be part of the same multiverse connected to the same Warp, and with some of the same Chaos gods and daemons appearing in and/or affecting each setting.

I have in recent months been charting the links in the lore between the Warhammer settings, and how they have evolved over time. These posts have been mostly (though not wholly) focused on the period before Age of Sigmar was launched, and have looked at various topics such as the legacy of the Old Ones/Slann, specific crossovers related to Chaos, and back when the Warhammer World was a planet within the 40k galaxy.

This is the first of three posts focusing specifically on the notion of a Warhammer multiverse with the Warp as the central connecting element, and it will start by looking at the current state of the lore.

In this first post, I am going to specifically chart the notion of there being a multiverse linked by the Warp with a cut-off point of roughly 2015-17ish and the launch of Age of Sigmar (AoS), and the Fall of Cadia and the emergence of the Great Rift (i.e. what can be thought of as perhaps the ‘current era’ of the lore for 40k and AoS). It will document how there is clearly and explicitly a multiverse, that it has officially been stated that it is linked together by the way the Warp connects to myriad realities, and that 40k and AoS are thus linked in this manner (though they are separate settings). Note: there are other kinds of alternative realities in the 40k lore I will not cover here (such as those used by the Necrons, like the Ghostwind) either because they aren’t presented as being accessed via the Warp, or they are sub-realities of the main universe/the Webway. They do, however, still play into the notion of there being a multiverse, with different realities and layers of reality. Warhammer metaphysics get complicated with talk of realities, universes, dimensions, realms, planes of existence, sub-realms, sub-dimensions and sub-realities.

The second post will look back at even older mentions of or depictions in the lore of there being a multiverse with different realities sharing the same Warp, evident in 40k (and Horus Heresy novels) and WHFB materials, going all the way back to the 1980s. That is not to say that such old lore (or all elements of that old lore) are necessarily relevant and in sync with modern lore as regards all of the specific details. Rather, it showcases that the broad concept of a multiverse with the Warp connecting to different realities has a long lineage, even if the prominence of this idea has waxed and waned over time. It has often been there in the background, getting sparse mentions which are easy to overlook. But the concept has endured within the lore.

The third post will go into depth discussing a recent White Dwarf article by games developers Phil Kelly and Andy Clark about the nature and place of the Chaos gods within Warhammer, which merits its own detailed commentary due to how much the article has to say, and the interesting and sometimes ambiguous nature of their statements. Viewing it with the lore covered in the first two posts in mind is, I feel, very helpful for making sense of what it has to say.

So, without further ado, let’s get to what the lore says and shows.

Quotes from the lore:

To get straight to the point, GW have explicitly stated that 40k and AoS (and thus WHFB, given that AoS emerged directly out of the destruction of the Warhammer World) are linked because they share the same Warp:

Q: Grombrindal – I have a question for you. There are four Chaos Gods in the Mortal Realms – Nurgle, Khorne, Tzeentch and Slaanesh. But wasn’t Slaanesh created by the aeldari in Warhammer 40,000? How does that work? Any words of wisdom?

A: Eugh, a Chaos question! I really must sort out my contract so I don’t have to answer them. Anywho… the Realm of Chaos is a mystical place that spans all of existence, stretching across dimensions and time – sometimes it’s called the Realm of Chaos, sometimes the warp, Empyrean, Immaterium, Formless Wastes, Land of Lost Souls or simply the Abyss – it’s all pretty much the same thing. In the Warhammer 40,000 universe it’s said that Slaanesh was created by the Aeldari. After his (or her) creation, Slaanesh was then free to journey across the Realm of Chaos, where he (or she) crafted a realm of pleasure and excess in which to dwell. From this point on, Slaanesh could send his (or her) minions – be they mortal or daemonic – across the Realm of Chaos, either into realspace, to the world-that was or now the Mortal Realms (and countless other places). Seeing as how similar the aelves are to the aeldari, it’s no wonder that Slaanesh took such an interest in them!

White Dwarf June 2018, p. 33.

This appeared in the 'Ask Grombrindal’ segment from White Dwarf, a column in GW’s flagship magazine devoted to answering queries about their games and settings, presented as being answered by the iconic in-universe character, the White Dwarf. Some people moan that this quote shouldn’t be taken seriously, but it actually reflects the way the lore about the Warp and the Chaos gods and daemons have been consistently presented in recent years, with the notion of the Warp connecting myriad realities (including 40k and AoS) having been reiterated many times, as we will see.

And here’s another even more recent answer from Grombrindal:

Q: Greetings, oh bearded and strong one. I was wondering how Slaaneshi daemons can be in the Mortal Realms as well as in 41st Millenium; I'm pretty sure that Slaanesh was created by the Fall of the Aeldari.

A: Daemons-what an unwholesome subject to be asking about! Especially those debauched Slaaneshi creatures. Quite why you would want to know about them. I don't know! However. I am oathbound to answer your question.

The Mortal Realms - and the Old World, which precede them - exist in a totally different reality to the 41st Millenium. The Realm of Chaos, where Slaanesh resides, exist outside of both these realities, although it is connected to them.

It is a strange metaphysical place formed of emotions, abstract concepts and ideas, where such mortal notions as causality and linear time have no meaning. So while you're right, and Slaanesh was created during the Fall by the hedonistic lifestyle of the Aeldari, the Dark Prince exist beyond time and space, and his minions can manifest in many realities. It's enough to make an old dwarf's head hurt.

White Dwarf 487 (2023), p. 5.

Now, some of this is phrased in a possibly slightly confusing manner, and it throws up all kinds of questions about how the settings can be linked, and how the Warp and the Chaos gods can be one and the same in each.

But, the Warp is meant to be confusing: https://youtu.be/aVfpUBtdGLs?si=7tkMLSvlwXSIxyFL&t=42 

Indeed, you can find a selection of quotes which showcase that the idea that the Warp is paradoxical and impossible to grasp also has a long and enduring heritage within the lore, here: https://madministratum.blogspot.com/2025/11/reminder-warp-is-explicitly-stated-to.html

This particular answer in the second Grombrindal article is interesting, because while it states that the settings are linked and share the same Warp (which has been true from the very start of 40k), it does say that the Old World existed in a different reality to the 40k galaxy, which was very much not the case in earlier lore, where the former was within the latter (You can check this post I already made about this topic to learn more: https://madministratum.blogspot.com/2025/08/the-warhammer-fantasy-world-was-once.html).

It is also worth noting that there are by now lots of quotes showcasing that the Chaos gods are universal in scope and active in other galaxies with 40k's universe, but I’m going to stick to material which relates to a multiverse and the Warp's multiversal nature. Some of these scenes I will survey should be questioned, as it could be construed that daemons and/or gods are afflicting people with visions which could be lies.

But perhaps they aren’t, and the statements/visions are actually true. Sometimes the most effective propaganda is grounded in truth, after all. The fact that they are in line with other statements presented via an omniscient narrator does, I feel, give them more weight. I have included such examples here for completeness sake alongside some commentary pointing out any issues as regards the need to critically engage with the relevant passages. Regardless, there are other bits of lore which are much more straightforward.

I will now provide a range of quotes working from the most recent backwards that showcase how the Warp (and hence Chaos) has been shown to link to countless realities in both the separate lores of 40k and AoS, and how Warhammer thus has a multiversal underpinning – along with some quotes which specifically link together AoS and 40k via their connection to the Warp:

To start, an interesting but obscure and ambiguous comment, which may or may not be relevant, is a comment  from a Loremasters video from Warhammer+ about the Nephilim Anomaly from February 2025 (https://warhammertv.com/details/25010?playlist_id=6), where we are told that there are various theories as to origin of Noctilith, a.k.a. Blackstone, with one being that it originated from another dimension.

Now, given that the Necrons heavily use Noctilith, that may imply that they procured it from another dimension via non-Warp based means (and we know they can access sub-realities). However, the fact that Blackstone can both nullify and amplify Warp energy (and was used to create the Blackstone fortresses, presumably by the Old Ones and/or the Eldar god Vaul), this suggests that perhaps it wasn’t of Necron origin. And we have the examples of Warpstone in Warhammer Fantasy which came from the Warp, and Nullstone in Aos which, as the name suggests, has some similarities to negatively charged Blackstone and which comes from the Aetheric Void (which, depending on how you view things, could be viewed as a separate reality to each of the Mortal Realms, given their fundamental differences in nature), which point to the fact that stones which affect Warp energy can come from other realities. While obviously not at all confirmed, perhaps this hints at the idea Blackstone could likewise have entered the 40k galaxy from another reality or sub-reality in a similar way.

And next, a quote which definitely is relevant:

Millions of years have not been kind to the Webway. Over the course of time, its circuitous routes have been ripped open and polluted by the followers of the Chaos Gods and all kinds of strange beings from multiple realities.

Warhammer 40k Leviathan Rulebook 10th ed. (2023), p. 163.

Now, this could be referring to places like Aelindrach, the sub-realm of the Webway which has been shaped by a different reality – but that is still an example of the Warp (in this case via the Webway, which is threaded through the Warp, creating a liminal space between the Warp and the Materium) linking different realities. Given other lore about the Webway and the Old Ones I will cover later, it seems that the Webway has enabled connections to other realities more generally.

Indeed, though unfortunately I don’t have access to a copy myself yet, but the 10th edition Drukhari Codex which has just dropped also talks about Aelindrach itself existing in several dimensions at once.

Next, a passage which isn’t explicitly a reference to a multiverse, but which likely is nodding towards that with its talk of different dimensions and “the veil” (a term to describe the barrier between the Warp and the Materium):

GIFTS OF THE OLD ONES

How the relics of the Old Ones were scattered across the Mortal Realms is a mystery. Their creators vanished millennia ago, and no sign of their presence has been detected since. Some slann propose that these constructs were fashioned from stellar materials that could survive the destruction of a world and were swept up as void-debris when the realms coagulated. Others theorise that they exist in multiple dimensions at once and 'phased' into reality at locations where the veil between worlds was thin.

Battletome: Seraphon 3rd ed. (2023), p. 13.

Now, all of these past few references link the Old Ones, who were a key connection between Fantasy and 40k in older lore – and, while ambiguous and shrouded in myth, there are grounds to view the Old Ones in 40k and AoS as still being one and the same.

Next we have something more daemonic, and remember that the Chaos gods have been explicitly stated to be one and the same between the Warhammer settings:

THE IMPOSSIBLE ROBE

The wearer of this robe exists between several realities at once. Thus can a daemonic commander potentially control Tzeentch's interests in multiple times and places simultaneously to further multiple aspects of the Great Plan. This effect makes it hard for foes to truly harm the wearer, who flickers between planes of reality in an unpredictable fashion. However, the robe is capricious, and has been known to rip its wearer out of reality altogether should they lose control of its powers.

Codex: Chaos Daemons 9th ed. (2022), p. 80 and also mentioned with the same description in Codex: Chaos Daemons 8th ed. (2018), p. 131 and War Zone Fenris: Curse of the Wulfen (2016), p. 193.

Note that this mentions several realities; so, more than just the 40k universe and the Warp.

And one which is perhaps a bit more ambiguous (and note that the nine dimensions relates to Tzeentch’s special number) as it may be taken as talking about dimensions and sub-existences of the main reality and the Warp, though it could also be taken to mean other realities:

WARPFIRE BLADE

Existing in nine times nine dimensions, the Warpfire Blade flickers with its bearer's sorcerous power. Every iteration of the blade strikes in differing forms and at varying angles - a plane of sharpened will, an outstretched hand of friendship, a wave of stellar fire - seeking a route through every sub-existence to sever the soul of those it strikes.

Codex: Chaos Daemons 9th ed. (2022), p. 80 and also mentioned with the same description in Psychic Awakening: Engine War (2020), p. 97

And:

Great horns are depicted curling from Tzeentch's head, crackling with arcane fire, while about him wheel endless expanses of sorcerous energy and overlapping, fractured realities. He is said to be able to observe the fates and machinations of any mortal being from any moment in time amidst these whirling images, and to hear the thoughts, hopes, plots and schemes of every living thing within his mind.

Codex: Chaos Daemons 9th ed. (2022), p. 17.

And a reference to the Eldar creating Slaanesh appears on a loading screen in the Warhammer Fantasy-set Total War: Warhammer III:

Slaanesh is the youngest of the Chaos Gods, birthed into reality by a cataclysmic display of avarice that echoed across the multiverse. Known as the Dark Prince and Lord of Excess, Slaanesh is the master of luxurious passions and also of cruel torments and despairing agony.

Image here: https://www.reddit.com/r/totalwar/comments/10wbqzg/well_this_is_interesting_yet_more_evidence_that/#lightbox (2022).

And we also have:

'But this is a catastrophe!' said Ku'Gath. 'My plague is nearly finished! I...I... I have crafted something special, something delightful that will kill the Anathema's son, spirit and body. This is as good as the plague that made me. It is better!' Ach, nobody cares,' said Rotigus, and dabbled his fingers in his bath. 'The Anathema's son,' he said mockingly. 'Oh do shut up. What is he? One man? One counterfeit demigod? This is the game of real gods! This reality is doomed, Ku'Gath. The mortals here are finished. They always lose, in the end, and this bunch have already lost, they just can't see it yet. The gods fight over the spoils, before the next corruption begins. Fresh realms await.' He gave Ku'Gath a sly look. 'Surely that makes even you happy, miserable one?'

…

'I might, I might. But I am busy on other worlds, on other planes, in other places. Severally, in matter of fact.

Haley, Godblight (2021), p. 54.

So, for the Chaos gods and their daemons, the 40k galaxy is apparently just one reality among many they can perceive and interact with from the Warp. And note, this is two daemons talking to each other, so there is no reason for them to be lying, as would be the case if they were talking to a mortal. We just happen to be privy to their conversation.

Guilliman, meanwhile experiences something which reaffirms the multiverse notion:

Information, too much information, coursed through Guilliman: stars and galaxies, entire universes, races older than time, things too terrifying to be real, eroding his being like a storm in full spate carves knife-edged gullies into badlands.

Haley, Godblight (2021), p. 298.

Note that the races older than time could be referring to the Old Ones, who have at various times in the Old Ones/Slann lore been said to have had an empire which straddled both different realities and across time. As charted in my previous posts, the Old Ones/Slann were a longstanding connection between Fantasy and 40k too.

And:

Duplicitous, manipulating and possessing knowledge spanning every time and realm of existence, Exalted Lords of Change ensure the Changer of the Ways' schemes are carried out as intended.

Psychic Awakening: Engine War (2020), p. 96.

The bolded seeming to imply there are lots of realms of existence. It would be weird phrasing if, for example, it just meant there were two realms of existence, the 40k universe and the Warp.

And here we have the seemingly reality hopping Old Ones:

The Great Plan of the Old Ones was impossibly vast in scale. The very stuff of universes was little more than building blocks to these beings, through which they could sculpt existence into their own, more ordered image.

Order Battletome: Seraphon (2020), p. 34.

Note it says universes, plural.

And this weapon, presumably of Old Ones origin and thus utilizing the Warp:

Blade of Realities: This pan-dimensional weapon exists to bring about the end of tyrants.

Order Battletome: Seraphon (2020), p. 59.

Next, visions experienced by Commander Farsight:

The galaxy screamed, and ripped along its length. The works of those long-fallen empires that had held back the dimension beyond reality had been purposefully shattered, hunted down and cast into the dust. The fabric of real space had weakened, thinned, and – like a dam broken apart by ceaseless impacts across its length – finally burst.

The terrifying truth of the hellish dimension was writ large, scarring the heavens with a lurid weal of purple, pink and blue. The disc-portal of Arthas Moloch was a single drop of poison in comparison to this ocean of toxic damnation, a rising tide of anarchy that would turn the history of the galaxy on its head.

A dread certainty slithered within Farsight's mind, a serpent slick with blood wrapping itself around his frontal lobe. This was no threat, no awful spectre of that which might come to pass should the evils of the galaxy be allowed to triumph.

This was the truth, and it was inevitable.

The visions sped up, battering at his mind, becoming a blur of motion that never ended. He saw every star in the night sky going supernova in quick succession. The tiny suns winked out one after another until the inevitable heat death of the universe stole the skies entire. In their wake there was only a burning god and his hateful brothers in darkness, their insane laughter echoing across the lifeless void as they sought new realities to corrupt and despoil.

Kelly, Farsight: Empire of Lies (2020), p. 197.

This is a Warp-infused vision, and so needs to be treated sceptically with that in mind – but it does support other bits of lore, including the fact that the Chaos gods have destroyed other realities, as we will see in various sources. Speaking of which…:

Esske used to be human, no more impressive in stature than the other tribally scarified warriors and athletes of his clan. He hails not from the Mortal Realms, nor even from the world-that-was, but from another time and place entirely – that darksome reality known in the Slaaneshi courts as the Land of the Forgotten.

...

In those dubious gardens, blood sports are a daily diversion for the daemons languishing between invasions of the mortal plane. Through illusions of a golden path, Esske was led to the outermost arenas, only to find himself fighting for his life in a giant oval of entwined bodies from which hundreds of daemons watched his progress. He found himself battling there for days, then months, then what seemed like an eternity, all the while sustained by the immortal energies of that place. Each new day he was matched against a procession of weird and terrifying creatures from a dozen dimensions, for the forces of Chaos have conquered many realities, and Slaanesh has retained keepsake souls and fascinating monsters from each and every one.

…

The legend of Syll’Esske is older than that of any Slaaneshi daemon save that of Shalaxi Helbane, the great hunter. So long ago did the story of the Vengeful Allegiance enter mortal consciousness that depictions of two conquerors, one standing upon the other’s shoulders, can be found daubed on the walls of Ghur’s deepest Primal Caves, within the Hyali Mosaics, and even in other worlds and realities entirely. Some of their exploits are particularly well known, for since Slaanesh blessed them in recompense for their service, they have carved a bloody swathe across the Mortal Realms and beyond.

White Dwarf October 2019, pp. 20, 26.

And:

Syll Lewdtongue has inspired thousands of warlords to acts of tyranny and misrule, but since uniting their powers with the megalomaniacal Daemon monarch Esske, the Herald of Slaanesh has become a force of conquest like no other.

Combine the might of a Daemon Prince and the cunning of a Herald of Slaanesh, and you get Syll’Esske – a terrifying tag-team skilled at carving a bloody path across the battlefields of Warhammer 40,000 and Warhammer Age of Sigmar alike. Capable of piling in and attacking twice, Syll’Esske is fantastic as a front-line combatant, as well as being armed with an arsenal of support abilities that’ll empower the Daemons they fight alongside.

From here: https://www.warhammer.com/en-GB/shop/The-Vengeful-Allegiance-2019?queryID=7f14a006409eeceaca7e3d28f0d96454 (2019)

Which really makes it clear that there are lots of different realities connected via the Warp, and 40k and AoS are just two of these. Esske doesn’t even originate from either reality, but has ended up a very active presence in the Mortal Realms of Age of Sigmar, and can appear in 40k.

And daemons can travel between realities via the Warp, as the next quote makes very clear:

Nurgle’s Rotten Legions in the 41st Millennium

The Realm of Chaos reaches through all space and time, existing in an infinite number of realities. As such Nurgle's servants are as likely to appear in 41st millennium as they are in the Mortal Realms. Yet while Nurgle’s servants – Pleaguebearers, Nurglings and Great Unclean Ones among them – exist in both realities, the Plague God also has daemonic entities that exist solely in the 41st Millennium – Daemon Engines.

White Dwarf January 2018, p. 41.

It is also worth noting that some daemon engines actually can and have appeared in Fantasy, as with Soul Grinders as seen in Warhammer Armies: Daemons of Chaos 8th ed. (2013), p. 57, and their appearance in the Total War: Warhammer games, such as: https://totalwarwarhammer.fandom.com/wiki/Soul_Grinder_of_Tzeentch.

And another quote about Nurgle daemons:

Atop a palanquin loaded with the paraphernalia of a mobile laboratory, Ku’gath is carried across the universes by a mound of straining Nurglings as he searches for the elusive combination of blights and woes that will recreate the perfect disease.

Codex: Chaos Daemons 8th ed. (2018), p. 51, previously published in the 6th ed. Codex in 2013 on p. 51 and 4th ed. Codex in 2008 on p. 48.

Now, this is a bit ambiguously worded and could possibly be construed as meaning two universes: the 40k universe and the Warp. But given other bits of lore we are surveying, I think is more logical to presume it is talking about a larger range of realities. The same is the case with the next quote:

It is said that when Khorne first created the Daemon that would become Skulltaker, the Bloodletter immediately chopped the head from the first creature he met – another Bloodletter. So began an existence of decapitation that has spread terror throughout the mortal and immortal universes.

Codex: Chaos Daemons 8th ed. (2018), p. 34 (first appeared in the 6th edition Codex from 2013, p. 34).

In isolation, this could be construed as referring to two universes: the mortal (Materium) and immortal (Warp). But it could also be taken mean myriad mortal universes, and maybe even myriad immortal universes, given the Warp itself contains many subrealms.

Next we have:

Of all the puzzles in the multiverse, there is but one that escapes Tzeentch's ability to solve - the Well of Eternity. Lying in the heart of the Impossible Fortress, the mystic Well is said to be the place where space and time originate and end. To understand it, Tzeentch would need only to enter its infinite depths, but even he cannot be sure of surviving the raging maelstrom. Unable to resist the temptation of unraveling the riddle, but unwilling to risk himself, Tzeentch grabbed his vizier, a Lord of Change known as Kairos Fateweaver, and cast him into the roiling currents of the Well.

Codex: Chaos Daemons 8th ed. (2018), p. 41.

So, an explicit use of the term “multiverse”.

And that time two Blood Bowl players ended up in the 40k galaxy, and a Genestealer ended up in their reality, from a 2018 short story I covered here: https://madministratum.blogspot.com/2025/06/two-blood-bowl-players-find-themselves.html

And another in-universe claim about Chaos having destroyed over realities, this time from Horus:

“I hear you, and I defy you.” Horus' words echoed down the aeons, coming from a place beyond time and space. "This universe will burn as countless others have burned before it! There can be no victory against Chaos.” If you cannot accept its power and its glory, then you shall die. The Emperor is doomed. I will kill Him myself.'

Haley, Wolfsbane (2018), p. 236.

So, it needs to be approached critically as claim from an in-universe character, who may be bullshitting. Indeed, Horus’s claim about killing the Emperor turned out to be wrong. That doesn’t mean his claim about Chaos destroying universes is though.

Indeed, continuing that theme, we have fact 186 from a list of 500 Warhammer facts:

When the world-that-was fell, Archaon wandered the multiverse destroying realities for Chaos before he arrived in the Mortal Realms. 

Listed here:

https://www.warhammer-community.com/2018/10/19/20th-oct-500-facts-for-500-stores/ (2018)

This is talking about the destruction of the Warhammer World from Fantasy.

And similar was earlier been stated here:

Archaon, Destroyer of Worlds: During the Age of Myth, Archaon waged wars across countless realities. He fought both for and against all four Chaos Gods, desecrating worlds in their name before slaughtering the champions sent to kill him. To the Chaos Gods he was both a powerful asset and a monstrous inconvenience, the very embodiment of Chaos.

White Dwarf Weekly 96 (November 2015).

We will come back to his exploits in more detail later.

Next, we have another 40k-centred reference to a multiverse:

Ka'Bandha fell through the hidden spaces between worlds. The occulted gears of creation rushed by him. In the machineries of being were the inner secrets of the universe displayed to him. The daemonkin of Tzeentch would have damned a dozen eternities for a glimpse of what he saw, but Ka'Bandha did not care for knowledge. The things on display were valueless to him, and the wonders of infinity whirled by unappreciated. Ka'Bandha fell forever and for no time at all, until a wave of change rippled out through the multidimensional space he infected, upsetting the delicate workings of infinite, interleaved universes.

---

The daemon recovered from his endless fall, beat his wings, and flew for a weakness in the fabric of all things. A single swipe of his axe split space-time, exploiting a faultline opened by the Cicatrix Maledictum.

Haley, Devastation of Baal (2017), p. 194.

And another AoS example, which again implies that Chaos has involved in the destruction of other universes:

The Lord-Celestant turned, and saw something impossibly massive looming above him in the raw skies of the Daemon realm. Its brass armour blazed like a hideous sun, and its enormous, hound-like muzzle was twisted in a monstrous leer. Eyes like colossal ruptured cysts gazed at him with inhuman hatred. In one talon it carried a black sword which still glowed with the heat of the dying universes in which it had been forged.

Reynolds, Black Rift (2017), p. 219.

And another AoS example, which implies Nurgle’s realm has consumed entire universes:

Through the ragged shroud of smoke, Gardus saw what lay below the Inevitable Citadel, at the heart of Nurgle's garden. Almost immediately, he closed his eyes and turned away, unable to bear it. It was impossible to describe. Impossible to comprehend. To his eyes, it was a wallowing swamp of black stars and dying worlds, of rotting galaxies alive with immense, writing shapes as large as nebulas. Cosmic maggots, gnawing at the roots of infinity. Galactic plagues, eating away at the very flesh of existence, reducing all that was to leprous ruin in their unending hunger.

…

He did not wish to see the swamp of dead universes swirling below, or the thing rising from within them

Reynolds, Hallowed Knights: Plague Garden (2017), p. 205.

And from the Hammerhahl Herald (2017), an in-universe AoS newsletter which used to appear on Warhammer-Community (Warcom), we got this image which tied in with the formation of the Great Rift in 40k and implied daemons from AoS were instead in the 40k galaxy capitalising on the Rift:

The Daemon hosts of Chaos were absent from the Mortal Realms today, as if called to battle on some other far-distant plane of existence.

Long-embattled Freeguild defenders took the opportunity to rest, feast, and drink heartily while the Stormcast Eternals took the battle to the mortal followers of the Dark Gods and toppled several fell citadels in the realms of Ghyran, Chamon, and Ghur.

Astromancer prognostications claim the eyes of the Chaos Gods are elsewhere today, but where and for how long, none can say.

Image here: https://www.facebook.com/WarhammerAgeofSigmar/posts/648121252051338/

And, back in 40k lore, details about how Eldar use the Warp to read the skein of fate:

But to be in it! All of reality was laid out before him. Threads twisted into yarns woven into tapestries depicting universes of possibility. Shards of infinitely shattering mirrors, each fragment showing the same event in different perspective; ripples alive with images on the surface of a lake, its depths also ablaze with scenes that were, could be, and had been. There were many ways of seeing the skein.

…

Before Slaanesh dragged him to her embrace, he saw the skein as he never had before, free of form's material trammels. It stretched away in all directions, a multiplicity of universes and futures. There, ahead of him, he saw the future of his race.

Haley, Valedor (2015), p. 25, 255.

Which could be viewed as showcasing merely possible other universes, though the second part does imply that other actual universes as well as possible futures are being seen via the Warp – and, as will be shown in the next post, the idea that the Warp connects endless alternative realities where fate branched in a different path had already been introduced into the lore. 

And, to finish, a very interesting but little known (at least among 40k fans) return to the issue of what Archaon was up to in the time between destroying the Warhammer World and arriving in the Mortal Realms of Age of Sigmar:

DESTROYER OF WORLDS

Little record exists of Archaon’s history before the beginning of the Age of Myth, save tales of blood and conquest told by dark priests and gibbering daemons. It was a time of savagery beyond the minds of men to comprehend, and an age when the Everchosen travelled between worlds seeking slaughter.

For unrecorded aeons, Archaon rode across the Realm of Chaos. Whenever he marched out from the impossible lands of that cursed dimension, no world was safe from his armies, and in the name of the Dark Gods kingdoms and empires burned and bled. Each victory proved once more Archaon’s mastery of war, and new trophies were heaped upon the idols of the Ruinous Powers. At his order whole worlds burned. Almost without counting were the grim legends forged in this time, and the Realm of Chaos still echoes to the dark tales of the Everchosen’s crusade.

By the light of the Sickle-thirst Moons, Archaon scourged the Yorndish Kingdoms and their so-called Indomitable Bloodline in the name of Khorne. A thousand howling Bloodletters watched as Archaon demonstrated his savagery, claiming the heads of all three hundred members of the Yorndish royal line in a night of wanton slaughter. By the time the moons set on the Yorndish palace, Archaon stood knee-deep in the tide of blood that flowed from its shattered gates, and a line of kings and queens that had endured for thousands of years was mercilessly eradicated.

Archaon brought the seven plagues of Nurgle to Shantor Isle and its protectors, the reputedly immortal Deepguard. Following the skaven of Clan Pestilens through holes gnawed in reality, his horde of daemons, infected mortals and ratmen spilled out into the island kingdom. The Everchosen led his rancid legions through the Coraltemples of Shantor, turning their halls black with decay. As they were cut down, the desperate Shantorian priests called upon their guardians, who were famed for their immunity to poison and disease. The Everchosen stood high in Nurgle’s favour, however, and when at last the Shantorian Deepguard staggered out to face Archaon’s armies, their joints were already swollen with fluid and their eyes weeped pus.

When the three-souled serpent god Y’ulae constructed the Star Crucible, Archaon forged an alliance between the Tzeentchian Sorcerers of Zyr and a cabal of Slaaneshi Spell-sirens, combining their powers to steal the celestial artefact. With a body made of light and fire, no blade nor hex could touch Y’ulae, and the magic hurled against it was as wind passing through the branches of a tree. Goading the creature into battle, the Everchosen used Y’ulae’s monstrous arrogance against it, sacrificing scores of screaming witches and sorcerers to its wrath. As his minions perished, Archaon snatched their souls from the air and used them to weave a sorcerous cage of prismatic mirrors around the beast. Blazing bright in its rage, Y’ulae’s body exploded in a thousand brilliant hues as the prisms channelled and dissipated its incorporeal form. As the creature’s dying wails faded away, Archaon claimed the Star Crucible for his own dark ends.

Archaon fought the long war against the Hedonshi Emperors, daemon lieges of Slaanesh. Massively bloated, the Hedonshi feared no mortal weapon, and ruled over hundreds of grovelling kingdoms from the spires of their golden palaces. With practised guile Archaon brought the Hedonshi tribute, plying them with an army of slaves for use in their sadistic rituals. As the Everchosen watched on with grim pleasure, the gluttonous daemon lords gorged themselves on souls and scented flesh. For six hundred and sixty-sixty nights, terrified slaves were herded into the palaces until Archaon’s ‘gifts’ did what no sword or spell could – the daemons ate uncontrollably until they burst, drowning their own vassals in torrents of noxious pink slime.

Chaos Battletome: Everchosen 1st ed. (December 2015), pp. 19-20.

It is important to understand that this is before Archaon appeared in the Mortal Realms, so these are worlds in different realities (which also lines up with the later references to his activies discussed previously) – which he was able to access via the Warp/Realm of Chaos. And, in one case, via Skaven Gnawholes (which are tunnels the Ratmen can burrow through the Warp to access different realms in AoS, and, thus, seemingly wholly other realities too.

So, that takes us back to the start of the ‘current’ era of the lore, to the big shake ups of the Fall of Cadia and the formation of the Great Rift, and the destruction of the Warhammer World and the creation of the Mortal Realms and launch of Age of Sigmar.

Conclusion

Hopefully that makes it clear that the current official state of the lore is that 40k and AoS are part of a broader multiverse, that they are linked by the Warp, and that some of the same exact entities (gods and daemons) appear in both because of this. It also showcases that some BL authors have also run with this concept.

As always, let me know if I have missed any examples.

Part two will trace the longer history of this notion of a multiverse linked by the Warp in Warhammer Fantasy and 40k lore. Tune back in tomorrow!*

*(Well, hopefully… time flows strangely in the Warp, after all…)

 Part 2 here: https://madministratum.blogspot.com/2025/11/a-deep-deep-dive-into-what-lore-says_10.html