Do not look up.
There are places in existence that do not belong to the dimension they occupy. They sit within it the way a splinter sits within skin — present, wrong, resistant to removal, and entirely indifferent to the discomfort they cause. The Sunken Forest is one such place. It is the only one that moves. It is the only one that is, in any meaningful sense, alive — because it belongs to something that is, and has always been, very much alive. What follows has been assembled from the accounts of those who approached it, entered it, and in some cases were permitted to leave it. The word permitted is doing considerable work in that sentence. It should not be overlooked.
The Sunken Forest is Vallath's resting place. His mindscape made terrain — the physical expression of his presence in a dimension he has chosen to inhabit, his will given soil and root and canopy and the particular wrongness of a space that belongs entirely to something that should not exist in any space at all. It did not grow. It did not accumulate over centuries the way forests accumulate, slowly and indifferently and without design. It formed around him, the way a shadow forms around what casts it, and it has been forming ever since — deepening, expanding, becoming more precisely itself with every year that passes inside it, which is not necessarily the same number of years that pass outside it.
It is permanent in any universe he has chosen to occupy. Not summoned for encounters. Not conjured as a weapon and dismissed when the weapon is no longer needed. It exists the way he exists — constantly, without requiring permission from the dimension that contains it, repositionable by his will alone. It has appeared without warning on the outskirts of cities that were not near any forest the evening before. It appeared on the horizon outside Edh Vaurn on the fourth day of that city's final week, four days ride from the nearest treeline, and those who saw it and understood what they were seeing reduced their count of the living accordingly. It does not appear. It arrives. Because he moved it. Because he wanted it somewhere, and wanting something, for Vallath, has always been sufficient.
From the outside it looks almost like a forest. This is the first wrongness and in many ways the most dangerous, because almost is a word that invites completion — that asks the mind to supply whatever detail is missing and smooth the result into familiarity. The trees are living. The right height. The right density. They move in wind that may or may not be present. But they are wrong in the way that a drawing of a tree is wrong — technically accurate, structurally present, and missing whatever quality it is that separates a rendered thing from a real one. Vallath has observed forests for longer than forests have existed. What the Sunken Forest contains is what he remembers of them, expressed through a mind that has never needed to stand inside one to understand what they are. The result is uncanny in the precise sense of the word. Familiar enough to draw the eye. Wrong enough that the eye, once drawn, cannot identify what it is looking at and cannot look away from the trying.
Areas of dead nature exist throughout. Patches of terrain that have reached their final state — bark that has gone grey and permanent, ground that has hardened into something that no longer has any interest in being ground, undergrowth that stopped in the middle of growing and has not resumed. These areas are not diseased. They are not decaying. They are concluded. Finalised. Small expressions of what the forest ultimately is — the resting place of the embodiment of endings, where Finality accumulates in the soil the way water accumulates in low ground, and the things that grow in it reflect what they have been growing in.
The approach produces the sensation of being watched. Animals do not enter. Birds do not fly over it. The silence at the treeline is not the silence of a quiet place — it is the silence of a place that has decided sound is not required here and has made the relevant adjustments, and when sound is heard, it is heard for a reason. Those who have stood at the boundary and chosen not to enter have reported, consistently, that the choice felt less like a decision they made and more like one they were permitted to make. That the forest could have had them. That it simply did not want them yet.
Entry is the last moment of certainty available to anything that crosses the treeline. The moment it is crossed, the treeline is gone — not obscured, not hidden behind what lies ahead, simply absent. The direction from which one entered is indistinguishable from every other direction, all of which extend identically into more forest, more of the almost-right trees, more of the weighted silence, more of the particular sourceless light that the forest produces from somewhere that cannot be located by looking for it. The forest is infinite because Vallath has made it infinite — not an illusion of infinity but a genuine spatial expansion, the same capacity that opens rifts in the fabric of existence turned inward and applied to the space within. One could walk in a perfectly straight line for the remainder of one's life and find no edge. One could retrace exact steps and not return to where those steps began. The forest does not loop. It does not repeat. It simply continues, because he has decided it should, and his decisions about space are not open to negotiation.
The sky changes. Upon entry the moon is gone. This is noticed immediately, and the noticing of it is the beginning of understanding where one is, though understanding does not help with the being there. What follows is slower. The stars go out one by one — not all at once, not in any pattern that can be anticipated, simply one by one at intervals that resist prediction — and as they go, what replaces them is not darkness. Darkness is the absence of light. What replaces the stars is the absence of the things that darkness requires to exist. The void. The space above dimensions. The substance from which absence itself is constructed. The sky becomes, over time, what existed before the first thing — what Vaelthr'uun looked down from before looking down at anything in particular. It becomes, in the most literal sense available, a window into what he is.
The dying of the stars is a timer. Not a metaphorical one. The longer one remains inside the forest, the more of the sky has been replaced by what lies above it, and the more of what lies above it becomes visible, and the more visible it becomes, the more difficult it is to avoid looking at it. Those who have been inside long enough report voices. Some of them belong to people who entered years ago and have not left. Some of them belong to people who entered centuries ago and have not left, because time inside the forest is not time in the way that time outside the forest is time. It is tangible in neither direction. Someone who entered in what their civilisation called the eleventh century may be encountered by someone who entered in what their civilisation called the twenty-first, both lost, both at different stages of what the forest does to people who remain in it too long, neither able to help the other and both aware of this in ways they can no longer articulate clearly.
Some of the voices are not survivors. Some are what Vallath has chosen to leave behind — spirits, remnants, presences that once belonged to people who entered the forest and whose bodies are no longer relevant to what they have become. They wander. They warn. Not out of kindness — the forest does not produce kindness, and what wanders in it has been in the presence of Finality long enough to have had kindness concluded out of them — but out of the compulsion that remains when everything else has been removed. They warn because warning is what is left. Do not look up. This is what they say. Do not look up. The ones who have looked say nothing. They are still in there, having looked, and Vallath permits them to remain because the ones who have not yet looked need to be able to see what looking produces, and the ones who have looked need an audience for what they have become.
To look up fully — to see the void that the sky has become, to perceive what exists above dimensions in the way that the forest eventually forces perception of it — does not grant knowledge. This is important to understand. It does not flood the mind with forbidden truth or bestow comprehension of things that were not meant to be comprehended. It simply breaks the part of the mind that was never meant to process what existence looks like from outside itself. One does not learn anything. One simply stops being able to not know that one saw it. And the not-being-able-to-not-know is permanent, and it is total, and it does not improve with time because time, inside the forest, does not improve anything.
Some leave. Vallath permits this selectively, for reasons that are consistent with everything else known about him. The ones he releases return to their dimensions changed in ways that are difficult to catalogue and impossible to reverse. They do not speak of what they saw with coherence. They speak of it constantly, in the way that something which cannot be processed continues to surface in every attempt at thought, the way a wound makes itself known regardless of what one is trying to do that is not thinking about the wound. He watches them return. He watches them attempt to reintegrate into the lives they left, and he finds in the watching something that functions, for something like him, very much like entertainment.
The Sunken Forest has no recorded location that remains constant. It has been reported on six continents across three documented universes, always without warning, always recognised immediately by those with sufficient knowledge of what to look for, and always by the time it is recognised already too close for the recognition to be useful. It is where he rests. It is where he keeps what he has collected. It is the one place in any dimension he has chosen to inhabit that is, without qualification or condition, entirely his. Approach it if you must. Enter it if you are compelled to. But understand, before you cross the treeline, that the forest has already seen you coming. That it has already decided whether you are interesting enough to be permitted to leave. And that its decision and his decision are, as with all things that belong to him, exactly the same decision.