The several posts that were made while I was writing this one seem perplexed by the distinction that Nu-Mantia (not me!) makes between Red Tower and the other towers. Make note of that. This will be an extremely heterodox interpretation of the Nu-Mantia Intercepts. However, it will be one which follows the Nu-Mantia Intercepts strictly and accurately. I believe that the current interpretation is entirely unsupported by the text itself.
Here is what the text says about the purpose of the Dawn Towers, Adamantia and Red:
Ada-mantia was the first spike of unassailable reality in the Dawn, otherwise called the Zero Stone. The powers at Ada-mantia were able to determine through this Stone the spread of creation and their parts in it. The powers also created Red Tower and the First Stone. This allowed the Mundus to exist without the full presence of the divine. In this way, the powers of Ada-mantia granted the Mundus a special kind of divinity, which is called NIRN, the consequence of variable fate.
This passage is quite explicit. The Zeroth Tower determined "the spread of creation," the First Stone "allowed the Mundus to exist without the full presence of the divine." The implication of the fall of Red Tower, thus, is that the world will cease to exist; "the gates of Oblivion will open" is a perfectly reasonable interpretation of this statement, supported by earlier references to the meddling of "Dagonites."
But
nowhere in the text does it say that the other Towers have anything to do with upholding the barrier between Mundus and Oblivion. They are not described at all like Red Tower. They are described as mimicking Ada-Mantia, in language that mimics the description of Ada-Mantia:
The Aldmer began to split along cultural lines, on how best to spread creation and their parts in it. Each Tower that was built exemplified a separate accordance.
That's right, the Aldmer, like the gods before them, use their towers to "spread creation and their parts in it." It seems rather fanciful to imagine any connection to the barrier with Oblivion in that. It is, moreover, not at all like the language used to describe Red Tower, which is the Tower whose fall is associated with Dagonites.
On the other hand, there is a straightforward explanation for the opening of the gates to Oblivion given by the last Intercept. Its stated here:
White-Gold Tower was made by the Ayleids, the Heartland High Elves that would have none to do with their isle-kind. Where the Altmer sought to focus on dracochrysalis, or keeping elder magic bound before it could change into something lesser (and act which ironically required aetherial surplus), the Ayleids harvested castaway creatia from Oblivion by entering a pact with the masters of the Void, the Princes of Misrule.
In other words, White Gold's very function was to interact with Oblivion, rather than Aetherius. Thus, when the Amulet of Kings fell into untrustworthy hands, those hands used it to open the gates of Oblivion.
In Nu-Mantia, the Ayleids, the Dagonites, and the Mythic Dawn all seem to form a continuity. The meaning of the text seems very clear: by obtaining the Amulet of Kings, the Dagonites are able to open the gates of Oblivion, which Red Tower once prevented. This can easily be reconciled with what
Oblivion says about the dragonfires and the Alessian Covenant, because there's no reason they could not have served a similar purpose as Red Tower, though this text just doesn't mention them. Only a rather impoverished misreading of Nu-Mantia could explain this terrible misconception that's plagued this community for so many years.