The Depths

**The Depths** is a large forest surrounding most of the landmass in Hell. It is widely considered to be extremely dangerous, to the point where anyone who goes missing in the Depths is presumed dead.

## Synopsis

The Depths is alluded to in chapter 12, but not explicitly mentioned until chapter 14, where Katsuki takes Izuku on a hike through the Depths.

## Properties

### Currents

The Depths has an unusual relationship with space, which is still not fully understood. Space within the Depths is driven by currents similar to those of an ocean, which are capable of carrying objects within across large distances very quickly. The lack of landmarks within the forest can make it challenging to tell that one has moved at all, and for this reason, standing still in the Depths is strongly discouraged.
Despite its hazardous nature, a relatively small subset of Demons still willingly enter the Depths in order to take advantage of the rapid transit facilitated by the currents.

### Awareness

Though most broad theories about the Depths' true nature are unproven (and often untestable), the Depths is widely believed to posses some level of cognition akin to awareness, or even sentience. This belief largely stems from one of the most bizarre phenomena of the Depths: the Depths Echo (sometimes called the doppelgänger effect, or the Depths siren). Within the upper levels of the Depths, the forest will commonly "speak" to travelers using their own voice, in an attempt to make them look in the direction from which the voice came. The Depths' efforts at communication become more coherent and sophisticated the deeper one goes, ultimately culminating in the manifestation of a physical doppelgänger at the lowermost levels.

There are many theories about why this occurs, but many believe that this is the Depths' way of finding the traveler within itself. The act of looking in the direction of the doppelgänger allows the Depths to orient itself around its target, presumably so that it can consume it.

## Levels

There are six known levels in the Depths.

### Daylight Depths

The shallowest level of the Depths. This level is effectively indistinguishable from a normal forest. In the Daylight Depths, the Echo cannot yet form words, and it is rare to experience it at this level.

### Twilight Depths

The next level of the Depths, wherein most visible light is lost. As the name suggests, the appearance of this level is reminiscent of twilight. At this level, the Depths Echo is capable of forming words, but not sentences. It is still relatively uncommon to experience it here.

### Nighttime Depths

The largest level of the Depths, comprising most of its area. At this level, all visible light is lost. The Depths Echo is much more common here, and it is capable of forming sentences that are structurally correct, but still lack substance.

### Midnight Depths

A relatively small, transitional level. This is the point at which the sound of wind blowing through the trees up above starts to fade. It is mostly defined for pragmatic (safety) purposes, as reaching this point is generally a sign that one needs to course-correct to avoid slipping into deeper, more dangerous territory. In the Midnight Depths, the Echo can form short but meaningful sentences. These usually take the form of commands; for example: "look at me." This is also the point when the Echo starts to manifest visually, though this generally amounts to brief flashes of movement out of the corner of the target's eye.

### Void Depths

The deepest level from which any Demon is known to have returned. It is at this point that the sound of wind completely disappears. Contrary to higher levels, where most creatures live at odds with the forest, creatures at this level often live in symbiotic relationships with the Depths. At this point, the Depths Echo can form complex, meaningful sentences, and will manifest as a physical doppelgänger that follows the target around. The echo will attempt to provoke a response from its victim through a variety of means, including, but not limited to:

* Preying on the victim's insecurities
* Bringing up past trauma to trigger a panic response
* Threatening the victim (or their loved ones)
* Exploiting sympathy (crying, false sob stories)
* Getting very close to the victim's face
* Sudden movements and sounds
* Self-mutilating

The combination of powerful creatures paired with the sophistication of the Depths Echo makes this portion of the Depths extremely dangerous.

### The Quiet

The deepest known point in the Depths. Little is known about the Quiet, but as far as anyone is aware, no Demon has made it out alive. There are many theories about the Depths Echo at this level, though its true nature is, at present, unknowable.

> "Personally, I think it’s God’s porn stash.” - Katsuki commenting on what he thinks is in the depths in Infero III: No Limits.
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## Inhabitants

The creatures within the Depths have a unique ability to sense the power of other beings. Thus, the danger of most beasts will depend on the strength of the traveler.

### Hyleks

Furry creatures that burrow inside of trees throughout the Depths. Harmless.

### Vassalites

Parasitic insects that enter through the orifices of larger organisms to lay their eggs. When the population within an organism reaches a certain point, they will assume control over motor functions.

### Cyclogeists

Large, fast creatures that dwell near the boundary between the Nighttime Depths and the Midnight Depths. Will not attack a more powerful being, but may attempt to steal prey.

### Deepseeker

Large creatures native to the Void Depths. Secrete a toxin that impacts muscle control, and makes victims suggestible. Extremely territorial.