Netherrealm

The Netherrealm (or Netherrealm) is a realm in the Mortal Kombat series. The Netherrealm is comparable to Hell in the Abrahamic faiths. It seems to resemble an eternal volcanic "continent", containing many volcanoes and lava pits.

About The Netherrealm
Shujinko: "This place... it feels dark."

Damashi: "As dark as every heart that inhabits it. Your presence here would not be possible. Only evil resides in this realm."

Netherrealm appears to be like Outworld, a realm composed of thousands of different layers. In the Mortal Kombat universe, deceased souls or entities who have committed major crimes descend into the Netherrealm to undergo endless torture. In fact, one cannot enter the Netherrealm without being evil or have a soul tainted with evil. It is an alternative, more generic name for the Abrahamic concept of Hell, as one of its former rulers was Lucifer (whose name appears only in the Sub-Zero game manual but not in-game). It is also described as "the darkest region of reality", and is inhabited by demons, monsters, and beings of the purest evil.

Though exits from and entrances to the Netherrealm are very limited for obvious reasons, the world had quite a tumultuous history. Millions of years ago, the fallen Elder God Shinnok was banished there. After ages of imprisonment, he was able to break free, deposing Lucifer in the process. He restructured the realm to bear some resemblance to Earthrealm, the world which he had long desired to make his own. He later used it as a staging ground for the invasion of Edenia, but found himself cast into the depths of the realm again after this invasion was foiled. The abandoned war machines of Shinnok were then put to good use by one of his former acolytes, Noob Saibot.

Two locations within this realm include the Bridge of Immortality and the Prison of Souls. These are almost like the Di Yu in Chinese Mythology. The Prison of Souls is the Chamber of Grinding and so is the Slaughterhouse. Shinnok's Spire resembles that of Yan Wang's spire in 'Journey to the West.'

In Mortal Kombat: Deception's Konquest mode, Shujinko arrives during the "Festival of Torture", in which dead bodies burn and inhabitants watch them.

Native realm species
In a generic sense, many demons and spectres are native to the Netherrealm in that human beings can be transformed into them when their essences descend into hell, but it is unclear if Netherrealm hosts any original life. It should also be noted that the inhabitants of this realm look more human than they are, because the realm's magical nature conceals their demonic nature. Once they leave the Netherrealm, they may start to decompose and rot. Like Chaosrealm inhabitants, some Netherrealmers tend to speak backwards.

A specific subset of demons, the Oni, is thought to be native to the Netherrealm. They vary a lot in terms of appearance, stature and color, as is evidenced by Drahmin and Moloch, and appear to be unable to communicate with other lifeforms. (Although in Armageddon's conquest mode Drahmin does state "Welcome to Hell." to Taven.) Their prime state of being appears to be one of unquenchable rage.

There are also seen dismembered humans, presumably from the Chamber of Dismembering.

Not born in the Netherrealm

 * Drahmin was once a warlord who was presumably assassinated, and transformed into a caricature of his former self by unknown powers, until he became an Oni. He may have been at the seventeenth level of Hell, seeing that he is somewhat eaten by maggots or he might have been skinned in Hell as well.
 * Noob Saibot is the altered form of the elder Sub-Zero, after he was murdered by Scorpion in retribution for his own killing. The mass corruption in his soul caused him to transform into a humanoid Wraith based on his reincarnation in the next life as he is not in a very low level.
 * Reiko was originally introduced as a member of the Brotherhood of Shadow, presumably a demon as well. However, his exact origin is revealed as Outworld in his trading card video.
 * Scorpion became a vengeful specter in the Netherrealm after he was killed by Noob Saibot (as Sub-Zero). Unlike most creatures in the Netherrealm, Scorpion is neither evil nor good and can somewhat withstand the torturous realm better than others stating that he is not at a very low level in Hell. In fact, it has been stated that his powers increase there as of Deadly Alliance. His type of reincarnation is based on the Chinese belief that a dead person with unfinished business comes back to settle scores with opponents and can't be easily put to rest.
 * Shinnok was once an Elder God, descended into Netherrealm because he wanted to take over Earthrealm without relinquishing his status as Elder God. However, he did overthrow Lucifer with Quan Chi's assistance and became supreme ruler of the dark realm as stated in the MK Mythologies manual but then, his side-story in Armageddon may retcon it otherwise. He is loosely based on the Chinese god of Hell Yan Wang and the Christian Satan, being deceptive and evil.
 * Smoke was brought to the Netherrealm by Noob Saibot. It is suspected he has also become tainted with evil after his new master altered his nanotechnology.

Native or unknown

 * Quan Chi's origin is not known other than the fact that he used to be an Oni, but one of the Netherrealm's demons claims that Quan Chi is a demon from the Netherrealm and was a member of the Brotherhood of Shadows.
 * Ashrah's origins are unknown. Once an assassin in service of Quan Chi, she found a sword (Datusha) that slowly guided her to the light side.
 * Moloch is also an Oni, but unlike Drahmin, he is more ape-like than humanoid.
 * The Netherrealm is also home to the Brotherhood of Shadow, led by Noob Saibot and Quan Chi.
 * Sareena is a demon of the realm, although little is known about her past. She was once a personal assassin of Quan Chi and served the Brotherhood of Shadow, but turned against the clan.
 * Kia and Jataaka were also demon assassins who served Quan Chi alongside Sareena. While they remained loyal to Quan Chi, Sareena did not.

Locations

 * Hell
 * Nekros
 * Netherrealm Cliffs
 * Prison of Souls
 * Pyramid of Shinnok
 * Sea of Immortality
 * Bridge of Immortality
 * Scorpion's Lair
 * Shinnok's Spire
 * Slaughterhouse
 * Cobalt Mines of Shokan (implied in Mortal Kombat: Conquest)

Trivia

 * The base area of the realm contains a city built by sorcerers, called Nekros, as a source of protection against the environment which drains life energies from the living.
 * Within the Netherrealm are Soul Stones, artifacts which can temporarily give energy to travelers to survive in the hostile environment.
 * Shao Kahn is said to have many allies in the Netherrealm, though no names are mentioned as to who exactly. Ironically, Kahn invaded this realm in Mortal Kombat 3.
 * The Netherrealm is one of the only two realms that is infinite in size.
 * References are made in both Scorpion and Quan Chi's bios to the "fifth plane" of the Netherrealm, where Scorpion was always reincarnated until becoming the Champion of the Elder Gods. This strengthens the parallels between the Netherrealm and the Abrahamic Hell, as Dante Alighieri's Inferno names the fifth circle as the abode of the Wrathful.
 * It is often said that only those with an evil taint can access the Netherrealm. However, some individuals were capable of accessing the realm:
 * Taven, in the Armageddon Konquest mode, is able to freely access the realm. It may be that Taven's half-god status allows him to enter the Netherrealm despite lacking the required evil taint.
 * Sareena and Sub-Zero, in her Armageddon bio, both of them were able to access the realm. Although Sareena's entrance can be explained by being of the Netherrealm, an explanation for Sub-Zero is not given.
 * The Elder Sub-Zero, in Mortal Kombat Mythologies: Sub-Zero, was able to enter, however Raiden stated that he already had an evil taint in his heart.
 * Shujinko, in the Deception Konquest mode, was able to enter in the Netherrealm by tainting his heart through working with the Lin Kuei, although it might have been because he was working for Onaga.
 * Nightwolf, in his Deception bio, is stated to have corrupted his soul with the Sin-Eater ritual, which would therefore allow him to enter the Netherrealm. After imprisoning Onaga in that realm, he was released from the realm.
 * Captain Marvel in Mortal Kombat vs. DC Universe was drawn into the Netherrealm by Scorpion's spear. Strangely he wasn't released from the Netherrealm, perhaps because the RAGE tainted his heart; even if there was an explanation, the point would be moot as the events of this game are not canon.
 * It is seen that some demons dislike the harsh environment of the Netherrealm, as both Ashrah and Sareena desired to escape.

Relationships with other realms
As one could expect, the Netherrealm could be said to pose the biggest threat to the Heavens, being its polar opposite. Most inhabitants of other realms fear the Netherrealm and avoid contact with it if at all possible. Under Shao Kahn's rule in Outworld, however, alliances have been formed between certain of its denizens and those of the Netherrealm (an example being the interaction between Shang Tsung and Quan Chi). Aside from that, it has no other known allies and seems to be viewed as a threat by the citizens of every other realm, being the place of eternal damnation.