There are times when a piece of media so heavily implies something that you can find yourself forgetting that it hasn't technically been explicitly established.
Back in Legion, or really when World of Warcraft Chronicle Volume One was published, the notion that Azeroth was a living planet with a soul became established canon. But while there's certainly tons of stuff that Blizzard has added in and retconned (I'm deeply skeptical that the Jailer was even conceived of before the development of the Shadowlands expansion actually began) I think this idea of a Worldsoul was probably there fairly early on. When we defeat Yogg-Saron in Ulduar, back in patch 3.1, the Old God refers to the world as "this miserable little seedling," clearly implying that there's something living within that can grow into something new. Now, I don't want to read too much into that: it's not obvious that at that point they had the notion that the Old Gods were sent to Azeroth for the purpose of corrupting the Worldsoul, and the relationship between Fel and Void (or, really, the lack thereof) probably took a while to develop, which is why for so long Voidwalkers were one of the staple demons we encountered in WoW, only seeing (at least the ones that aren't Warlock minions) them reclassified as Aberrations quite recently (maybe as late as War Within? I could be wrong there). In a similar way, I imagine that it wasn't really until Chronicle came out (or rather, until they started hashing out Chronicle) that they even really hammered out the notion that Necromancy and more broadly Death Magic was its own fully separate thing in contrast with Shadow and Fel magic.
Indeed, this complicates the narrative of the creation of the Lich King: as established, Kil'jaeden originally bound Ner'zhul's soul to the armor like Alphonse Elric to make the first Lich King, and if I recall correctly, Frostmourne's origins were slightly hazy, but was likely sealed up in the Frozen Throne (or rather, the crystal that would come to be called that) along with Ner'zhul. Thus, the Scourge's necromantic magic was assumed to be a kind of derivation of the Legion's demonic fel magic. (Though I also believe that there was some dubiously canonical notion that necromancy was actually a branch of Arcane magic). Given how much I love the Scourge as bad guys, I was actually really appreciative that they were fleshed out as representing their own separate cosmic force, but the messiness of the Shadowlands expansion undercut some of this appreciation (including a total lack of even one throwaway line to explain how Kil'jaeden learned of the Helm of Domination and Frostmourne, and how he acquired it. Literally just one little reference to the demon lord investigating obscure tomes of necromancy and whispers of a shadowy realm beyond the physical would have done it for me.
(Actually, sorry, gotta rant here: I wish the Shadowlands had been something more similar to D&D's Shadowfell, a kind of dark and macabre reflection of the real world. I would have been totally fine with an entire expansion that had the gothic and spooky aesthetic of Revendreth. Mind you, WoW's take on Planescape would have also been very cool, but I just think that the way the Shadowlands fits into WoW's cosmos is just kind of unsatisfying. Are we to understand that all those people faithful to the Light went off to an afterlife that didn't really do that?)
But let's pull things back and talk about the post-Shadowlands lore, given that there's a strong chance that at least some of that stuff is going to get retconned away given its unpopularity (there are aspects of it that I do really like, to be clear, and I'm not as much of a Shadowlands hater as some people are. Warlords of Draenor remains the worst expansion).
Ok, so, we know that Azeroth has a soul, this Worldsoul that is the real living, conscious, and seemingly benevolent heart. There's something special about it that makes it the envy of all the other cosmic forces in the universe, with documented cases of the Burning Legion trying to destroy it, the Old Gods (and now Xal'atath) trying to corrupt it, and the Jailer trying to dominate/seize it. Indeed, the actions of the Pantheon actually follow a similar pattern - heavily changing Azeroth in an apparent attempt to ensure that the Worldsoul is eventually born as a fellow Titan dedicated to the Ordering of he cosmos.
Now, to back up: in Chronicle, it's flat-out stated that what a Worldsoul is is a kind of fetal Titan - that it is natural and expected that once its long gestation is completed, it will emerge as a Titan. Aman'thul is depicted, along with the rest of the Pantheon minus Sargeras, as unambiguously benevolent in his intentions.
But not to whitewash things here: our first real exposure to anything Titan-related was Uldaman, where we fought Titan creations, including Archaedas as the final boss. While this puts us into an antagonistic relation with him, to be fair, I'd argue this was a bit more of us barging in and killing him for no really good reason. But later, we saw how the Reorigination protocols callously threatened to wipe out every living thing on the surface of Azeroth during the Ulduar raid. Again, this was probably a really serious "last ditch-contingency" plan that you could forgive perhaps if the assumption would be that the alternative to setting it off would be the reestablishment of the Black Empire. We did also see how Titanforged peoples were not necessarily benevolent: the Mogu were brutal tyrants over Pandaria, and while they were clearly going against "programming," and turned against Ra-Den, it shows that the Titans' works didn't always mean the best for everyone on Azeroth.
But it really wasn't until Dragonflight - which is the first expansion of the really "modern" era of WoW - that the benevolence of the Titans was truly put into question. There's significant implication that the waters that feed the Ruby Life Pools carry with them a kind of magical indoctrination, ensuring not only that dragons undergo the physiological change from their original proto-drake bodies, but that they are inclined to uphold the Titans' vision for what Azeroth ought to be. This is the real crux of the Primal Incarnates' fight against the Aspects, the Incarnates viewing this reinforced allegiance as a corruption not unlike the Curse of Flesh from the Old Gods (the Curse of Flesh technically being more like a computer virus entered into the Titan creation forges. Interestingly, the Orcs are also flesh-and-blood despite descending from a Titanic creation, though that process and history was wildly different. Hey, do the Orcs know that they're more closely related to humans, dwarves, and gnomes than you'd expect for creatures from another planet?)
In the Emerald Dream, we find some record (I think a book of some sort written by dragons) that suggests that Aman'thul was opposed to incorporating the power of Life into their creations, fearing the lack of control from some other primal magic, though I also believe the Titans are actually quite comfortable wielding the Light.
And Aman'thul really does become this kind of centerpiece of doubt as to the Titans' ultimate motives. He is the oldest of the Pantheon, and in the mythical ancient history, once he was born, he went around and nurtured other Worldsouls until they were born as Titans, collecting this family as he did. But were they bound to be born similar to him? Or did Aman'thul help to shape them, creating Titanforged facilities and servitors on these worlds to cause them to be born as Titans and not some other thing? Is what it means to be a Titan something that Aman'thul invented as a reflection of himself?
I'll note that this might not be inherently a bad thing, but it is an act of will upon the cosmos that might have precluded other possibilities. Had there not been this intervention, might Khaz'goroth, Norgannon, Golganneth, Eonar, Aggramar, and even Sargeras been profoundly different kinds of beings?
We're told that, to begin with, Azeroth was a world of elemental chaos. Because the Worldsoul was so much more powerful than those of other worlds, the kind of fifth element (of six, actually) known as Spirit, which binds and balances the four classical elements to work in harmony, was scarce, most of it going to feed the voracious Worldsoul, and thus causing the four elements to clash in endless conflict. (Notably, Draenor didn't have a Worldsoul at all, which allowed there to be an abundance of Spirit, and for that reason, the elements on Draenor are very cooperative, its four equivalents to the Elemental Lords just chilling peacefully together in Nagrand. No wonder Shamanism came easily to the Orcs). I will say that I wonder what relationship, if any, the Primal Incarnates had with the Elemental Lords. Each of the Incarnate represented one of the classical four elements, like the Lords. But did Raszageth have a particular relationship with Al'Akir? We do see Fyrrak allied with Smolderon (the heir to Ragnaros that Shamans anointed as the new Firelord in Legion. Guess we gotta find another one).
Anyway, the elemental chaos gets taken over by the Old Gods (another group of four, though no obvious elemental theming there. I do feel like sets of four is a really common motif in WoW for whatever reason,) who force the elementals to fight in their endless wars (the elementals were doing that anyway, but maybe didn't love having these new masters) while they build their Black Empire.
This is when the Pantheon finds Azeroth, and decides to remove, and then when that doesn't work, simply contain, the Old Gods, crafting the Titanforged to destroy the Black Empire and the Manifold to repair the damage but also set Azeroth on the path to Titanhood.
Now, we finally get to what I was referring to at the start of this post:
It would seem that Harandar is the location where the Worldsoul originally sat. Harandar is a place of lush life, most of which is plants (even the dinosaurs and birds).
Now, there's a funny little question of continuity here: Harandar is where the roots of the World Trees all converge, somewhere deep below the surface of the planet (is it meant to be in its core? If so, Azeroth's geological structure is very different from Earth's, because that deep you'd be in a giant sphere of metal). The roots all kind of converge to form a cradle where the goddess Aln'hara once rested, long ago.
Here, the super-heavy implication is that Aln'hara is the Haranir name for the Worldsoul of Azeroth. There's a lot of evidence to support this. The Haranir experience of receiving visions from the goddess looks very similar to the way that the Worldsoul contacts others on Azeroth. Furthermore, the Aln Dust that we must gather to suppress the overpowering psychic voice of the goddess has a blue-and-gold color scheme identical to the color of Azerite that we encountered in Battle for Azeroth - again, I think the only reasonable conclusion we can draw is that Aln Dust is like, powdered Azerite (perhaps a different kind of Azerite, but from the same source. We can also presume that the special water from the Well of Eternity that Ilildan collected before the Sundering, and which served as the source for both the water that feeds Nordrassil and the Sunwell, was likely liquid Azerite or perhaps some kind of Azerite solution).
But here's where the continuity gets funny: my understanding is that Nordrassil was the first World Tree, and it was planted at the end of the War of the Ancients - and while that is, yes, long ago, it's still relatively recent compared to the Ordering of Azeroth, when Aln'hara/the Worldsoul was relocated to the Worldcore. Indeed, Teldrassil, itself was only a decade or two old when it was burned, created specifically to be a replacement for Nordrassil after the damage it took in the defeat of Archimonde. But likewise, Vordrassil was a project of Fandral Staghelm, when he was acting as the Night Elves' archdruid while Malfurion slept in the Emerald Dream (remember when he was one of the two Night Elf racial leaders? No? Man, I'm old,) which certainly had to happen post-War of the Ancients.
In other words, what roots actually made the cradle? Were there older World Trees that have been forgotten or lost? Were these actually the roots of G'hanir, the mother tree, from whom the other world trees were, like, graftings? G'hanir exists within the Emerald Dream, but it doesn't seem that hard for me to imagine that its roots reach out into the physical world to cradle the Worldsoul.
Next, I want to talk about the Rift of Aln.
When the name "Rift of Aln" was first introduced (I can't remember where, but it was at least part of the lore by Legion, though I think it might have been mentioned as early as Vanilla,) it was simply known to be the part of the Emerald Dream that was where the Nightmare was strongest, perhaps its origin point. The Rift of Aln is where we fight Xavius in the Emerald Nightmare raid, beyond which we find the "heart of the dream."
My assumption was that the Rift was, unlike most of the locations we saw in the Dream, not the counterpart to any location in the physical world, but a rift in the fabric of the Emerald Dream. Its vague, misty form when we face Xavius (kind of a grey void other than a lattice-like pattern above us, which to be fair, doesn't not look like the goddess' cradle in Harandar).
So I was kind of surprised when I did the quests in Harandar and found that there was, in fact, a real place of the same name on the physical plane. The Rift of Aln in Harandar looks very different, though given how empty a void the one from the raid is, it'd kind of have to be.
Now, the "Aln" part of the name makes sense: it's related to Aln'hara (I'm sure this was arrived at backwards, with the name Aln'hara created to incorporate Aln into it, and Hara linking her to the Haranir). But I also think that the Rift of Aln might actually start to give us some clues as to the nature of Azeroth/Aln'hara's unique powers that have made everyone so eager to claim her as one of their own.
The Rift of Aln is filled with weird kind of dream-creatures, beings imagined into existence by the Worldsoul. Even though she's been away from Harandar for a profoundly long time, this lingering echo of her dreams remains. And these dreams seem to be beings of great power - the Haranir who go there have to be ritually severed from their psychic connection with the Worldsoul so as not to have her lingering psychic dream-energy overwhelm their minds and drive them to madness - a madness nor born, I think, out of any malevolent intent, but just a being so beyond mortal comprehension that getting a direct feed of her thoughts would be like filling a water balloon with a fire hose.
Obviously, it's hard to gauge via game mechanics how powerful these monsters are compared to these other monsters, especially with level scaling, but we do have one pretty important example:
Ula'tek.
See, in the distant-past prologue during the quests that led us into the 12.1 content, we find that the Amani shaman, Nek'zali who summoned Ula'tek with dark, sacrificial magic says she is pulling this creature from a "Rift in the world," which to me suggests she's conjuring the kaiju-like hydra from the Rift of Aln.
Is it possible, then, that Ula'tek is, in fact, some kind of dream-creation of Aln'hara's? Ula'tek's creation may not have even been intentional - just some kind of psychic manifestation of a weird monster born out of this vast, incomprehensible mind. Was Ula'tek always intended to protect Azeroth? Or was she actually some kind of nightmare? A primordial embodiment of viciousness and terror?
Perhaps Nek'zali's ritual didn't just teleport Ula'tek from the Rift of Aln to the Coiled Isle, but might have actually given physical form to this nightmare of the goddess.
Now, tying this back together:
My belief is that Tyr's flight to what is now Lordaeron happened before the Sundering, and actually a big part of that is because of Kith'ix, whose downfall led to the rise of the Amani Empire. And generally speaking, I think that the major Troll Empires all pre-dated the Night Elf empire that would dominate ancient Kalimdor until the Sundering. (This does also mean that Azeroth's modern humans have been around longer than ten thousand years. It would be weird for such a widespread species on Azeroth to have literally not existed before many player characters in WoW were born. My Draenei Death Knight is a minimum of 25k, and don't give me any damn "space travel time dilation" stuff. The Draenei make the Night Elves look short-lived, and that is a bit of canon I will never let them take away).
So, timing-wise, we know that Ula'tek was dreamt up by the Worldsoul long ago. Maybe it was even before the Ordering, given that we don't know if the Worldsoul's dreams continue to manifest in the Rift of Aln (and I'd guess not, as I assume that the reason that location in particular is where these manifestations arise is because of its proximity to the Worldsoul's original location).
And perhaps this is the power that makes Aln'hara/Azeroth so unparalleled: this ability to dream into existence extremely powerful things might not really have precedence. Even unconsciously, Azeroth can will things into existence.
Ok, last major topic: dreams.
Azeroth's dreams manifest in the Rift of Aln. The Rift of Aln within the Emerald Dream is the core of the Nightmare, but it's also seemingly the passageway into the Heart of the Dream, where Malfurion takes us at the end of the raid.
The Nightmare itself is relatively recent - it began with the planting of Vordrassil in Northrend (the massive fallen tree in Grizzly Hills,) as a means attempted by Fandral Staghelm to seal off some of Yogg-Saron's leaking corruption. That backfired by instead allowing the Old God corruption into the dream via the tree. (I'm not going to get into why N'zoth wound up feeling more associated with the Nightmare than Yogg-Saron, because I honestly don't have much of an explanation for that).
But it seems that the association between the Rift of Aln and both dreams and nightmares (obviously both being essentially the same thing) dates back long before its association with the Emerald Nightmare.
Instead, what I would guess, is that the Rift of Aln, and Azeroth's dreams, are the basis for the Emerald Dream itself. While there's some credit claimed by the Titanforged Keepers, Freya especially, it was always left open that the Dream wasn't created by Freya so much as it may have been simply discovered by her. The origin, I would think, is actually the Worldsoul.
Which... I don't think is even very controversial a statement. But I think we're seeing these loosely-connected ideas tied together more firmly. It also, I think, makes the strategy of the Old Gods to corrupt the Dream make more sense: if the Emerald Dream is something of a direct path into Azeroth's very mind, then it's a great avenue to introduce your corruption to the world on a psychic level.
I think this might actually give us an answer to the origins of Ula'tek, but it also buttons a few things up in a way that actually makes decent sense.
Again, technically the game has never outright stated that Aln'hara is the Worldsoul of Azeroth. But, like... there's no way it isn't, right?