To which we come full circle in this topic … as that’s likely the very thing they’re hoping to remedy.
You’re naturally not alone to feel that way about how things were presented.
And I’d posit that is precisely why it makes sense that they’re potentially trying to diminish the impact that the Shadowlands expansion had by recontextualizing the existing framework we were given surrounding the First Ones by instead further clarifying how it was imposed upon the cosmos atop some kind of existing baseline.
The way I read this is that Sylvanas is suggesting that the realm and force of Death is … merely an ordered machination of an afterlife. That the cycle we know, the cycle as put in place by the First Ones as we’ve now been told recently, is merely a shadow of true death. That there is something else hiding under all that structure, something real.
Death is a cosmic force put into the cycle and structure by the First Ones, this is known [so far].
On the level, seemingly, of the rest of the five cosmic forces.
But what if it is truly a difference between Death and … death?
Why? I wager [as I’ve mentioned on these forums and in this topic before] that they were hoping to escape death. They imposed a structure, a failsafe, a contingency, that would allow them and all other beings of these forces to return to their point of origin upon death; their force of origin. Yet, if they were killed in their native plane? What then?
As we’ve been told, you just … disappear. Yet where to? Double death?
As I’ve presented on these forums before, three of the six forces and their planes have been shown to work the same way, thus a likely truth for all six:
My own personal hope is that the First Ones were mortal, to some degree.
They “forged” the Pantheon of Death and the Pantheon of Order—one in Zereth Mortis and the other in Zereth Ordus—meaning it’d be kinda strange if they themselves were created as such. It would make more sense, as I’d argue, for these First Ones to create new beings in their image. A tradition then carried by the Titans with their creations.
They did this because they are or were not constructs.
Hopefully, as my own opinions read, they’re beings of Spirit. Likely more elemental.
Which would explain its abundance in the Great Dark Beyond; why and how it is only found in the Great Dark; why it is outside of the cycle and only loosely related to the other forces. This is the “Plane of Spirit”, to put it simply.
Spirit energy, also called Spirit of Life or Spirit of the Wilds,[2][3] and referred to as Chi by monks,[4] is the fifth element,[5][6] the inner energy[7] inside all living beings.[8][9] It is the spark in their hearts that connects the mortals even to the elements.[8] Decay is the opposite of Spirit.[4] It is believed that both Spirit and Decay influence the soul’s creation of anima.[10]
Spirit brings balance to fire, earth, air, and water, and the reason that Azeroth’s elementals are so chaotic is because, as it developed, Azeroth’s unusually vast worldsoul consumed much of planet’s Spirit.[11] On worlds more plentiful in spirit like Draenor, the elementals are calmer and work in harmony.[12] In fact, Draenor had so much Spirit that it caused accelerated plant growth, giving rise to the Sporemounds.[13] Spirit has also shown the ability to turn stone into flesh over time. The magnaron were infused with spirit energy by the spores released upon the Sporemound Botaan’s death, turning them into flesh in the form of gronn, and then ogron, ogres, and orcs over thousands of years.[14]
https://warcraft.wiki.gg/wiki/Spirit_(lore)
It is that uncomfortable mortal coil the First Ones possibly saw as their weakness.
And it alone was not enough for what could be, for how they could shed that mortality.
This contingency was a way to escape that inevitable fate, to sweep it under the rug with a universal rule that dictates their cosmos in which it is avoided at all costs. Mortal beings terrified of what lay beyond, same as most of us, and trying desperately to avoid their fate. All the planes were created this way, the pantheons we have yet to encounter.
But it wasn’t fool proof, it wasn’t perfect. Because you could still disappear.
Why did they [the First Ones] do this? The Titans made the Keepers and subsequently the Watchers and their titan-forged to do their work, ensure their work, in their absence.
… Could it be that simple? That they in turn are of the mortal plane? Merely absent?
That all these beings were created as custodians in their stead?
And why has all these forces potentially invaded our space?
The Titans, the Demons, the Naaru, the Void Lords.
Why aren’t they in their own planes of existence? The Plane of Order, the Plane of Light.
Why is this existence, this mortal plane, so lucrative?