While there is a plethora of mythologies that bifurcate the world into distinct dominions of heaven and hell, such as Christianity, this dichotomy isn't entirely accurate. The Severed Realm closely resembles the traditional concept of hell. It's the resting place for wayward souls after death, particularly those unable to liberate themselves from the negative emotions that tether them to the material plane. Consequently, souls retaining their anger, hate, envy, and similar sentiments are cut off from the other realms, ensnared within the Severed Realm. Over time, these negative energies corrupt the soul, transforming it into a demon. These demons populate the Severed Realm, gorging on the energies of souls yet to relinquish their ties to this realm, or release their burdens and earn freedom.
Attraction of Negative Energy
This plane could also be conceptualized as a "negative energy plane," acting as a magnet for similar energies from the cosmos. Although the material planes are composed of diverse energies, the contents of this plane are primarily pure negative energy. However, this doesn't denote negativity in an electromagnetic context, but negativity detrimental to life - an anti-life energy. In some respects, it's the inverse of Aether, and in others, a corrupted version of Aether. It's the result of primal elemental forces that constitute life becoming tainted and destructive rather than life-giving.
Objects infused with such energy gravitate toward this plane. Its power can be harnessed to pervert life, as in necromancy, which taps into this plane to reanimate the deceased. Since death is a natural component of life, its reversal via magic signifies a corruption of life.
Shedding Negativity
Escaping this realm requires a soul to shed its negative energy, an act inherently fraught with the risk of instigating corruption. A more apt description would be the necessity for one within the Severed Realm to purge their own corruption to facilitate escape. A deceased soul can perform this easily, being pure energy, and the absence of physical form simplifies the separation of corruption from life. However, for a living entity, such as a human, this process is complex and carries repercussions. Releasing one's negative energy within the Severed Realm can offer a route to escape, but a new seed of corruption will be drawn in. The return journey to the material plane from the Severed Realm is costly and could result in severe consequences if the seed of corruption is left unchecked once the person re-enters the realm of the living.
Physical Properties
The Severed Realm manifests as a barren wasteland, stiflingly hot and humid in an intensely uncomfortable way. There are virtually no traces of life or positive energy there. Though plants do grow, they're twisted versions of their material plane counterparts. Consequently, these plants are typically toxic, and the non-poisonous ones tend to feast on the flesh or souls of visitors. Any plants that can be eaten usually possess venomous qualities or some other sinister means of making death seem merciful. Running water exists, but it's brackish and dirty, teeming with harmful poisons and parasites that can be fatal swiftly. Expertise in elemental manipulation or specific magical energy usages can purify items found in this realm. Scientific methods can also be employed to evaluate the extent to which found items can be safely consumed, given sufficient knowledge of poisons, parasites, and other lethal factors.
Magic, Psionics, and Aether
Given that this realm is a bastion of corruption, it's an inevitable consequence that the use of magical or psionic energy exposes one to the negativity and corruption of this place. The effects accumulate, and individuals with weaker mental fortitude risk succumbing to the negative energy and corruptive influence of the Severed Realm.
Death is No Respite
Here, death offers no sweet solace; instead, the plane actively seeks to corrupt and/or kill anyone who dares to enter. If one perishes here, their soul risks permanent corruption, and even if it resists, they will face a fierce struggle to shed their negative energy before the corruption becomes so pervasive that escape becomes impossible.