The Underworld (also known as the Underground, Hell and Heck) is the main setting for the Grim Tales series.
"There is far more to the 7 realms of Hell than meets the eye. For within the dephts of the Underworld, there consist many realms of which of the most feared and dreaded beings of existence dwell. And of these domains there lay five known to the denizens as the most cautioned of all."
A long time ago the Underworld, back then known as the Underground, only consisted out of a few areas but greatly expanded after a certain event. At first it consisted out of The Ruins, Snowdin, Waterfalls, Hotlands and The Core. However after Sans and Papyrus became the leaders of the Underworld it slowly transformed into a place consisting out of multiple realms.
Sans created these realms and assigned leaders to them in order to have a more structured Underworld and that he wouldn't have to do much anymore as leader himself. The portal to the Surface was closed, although special ways have been created to traverse between the Surface and the Underworld.
Long before the creation of the Underworld there was the Underground and in the Underground was Snowdin. Despite being subterranean, Snowdin is somehow covered in a perpetual layer of ice and snow. The overlord ruler Sans resides in a simple cottage in the place along with a few others VIPs. No one is able to enter or exit Snowdin without using the Cthulhu Express with the sole exception for Sans. Popular locations within Snowdin are Grillby's Bar and Alphys Laboratorium.
Standing high above Snowdin is Bald Mountain, in the past called Mt. Ebott. It was a high mountain with the top missing and allowed human to fall into said mountain to find themselves in the Underground. Once Sans ascended the throne he made sure no human could enter the Underworld ever again and set up Chernabog to be the keeper of the mountain.
Necropolis is home to "The Lord of Death" Grim the Reaper and his wife Queen Mandy, who throughout the underworlds is known as a feared and ruthless dictator silently referred to as "The Queen Bitch". The Castle of Grim consists of a jagged mountain terrain, near impenetrable fortress walls and armed sentries at every corner. However, it is said if one should manage to find their way through the castles' mazes and defenses, untold riches and power awaits them worthy of godhood. That is if they can survive the "Bitches" wrath.
One may also visit the Land of the Dead which is adjacent the Castle of Grim, overseen by Death who most often spends his time in his zen garden or playing music in his home. He shares his overseeing with Sartana of the Dead who oversees Terra de la Muerte, a place where the dead live who return every year to see their family. One may come her for concerts, a nice drink and entertainment as it is a lively place in a land of dead. Sartana however desires more than this tiny piece of land.
Land of Tainted Souls
A near barren wasteland of sun hot rocks and even hotter lava. The Land of Tainted Souls is referred to by many as the "Fires of Hell", and it is here that a devil so wicked and vile that even his name remains unspoken reigns, named "HIM". "HIM" is as cunning as he is known, as every ruler in the underworld knows of his slick and sadistic nature which he uses to get what he desires or manipulate those that he wants to have work for him do his bidding. His cruelty and conniving nature is said to put him only three steps shy of the underworld's "Bitch Queen.
City of Aku
A Metropolis based realm where all of its inhabitants give hail to the retired, though still acknowledged Master of Darkness, Aku. Though not seen as ambitious, as many of his fellow demi-immortal cohorts in evil are, Aku is a respected overlord of the Underworld and is feared not just for his immense power but for his knowledge as well. It is a world that closely resembles our own where it's inhabitans indulge themselves in the guiltiest of pleasures.
A city based realm of the Underworld where demonic and deathless entities reside. Home of Hunson Abadeer aka "The Lord of Evil" the Nightosphere is a dimension which at times is as random and unpredictable as its ruler. Where the sickest thing you can do is have too many bananas and any questions asked would, for the best of the individuals' well-being, be better off to kept to ones self. Though there is one things that remains clear in the Nightosphere and Hunson Abadeer approves that statement that; "No one leaves the Nightosphere.
A dimension of the Underworld which is ruled by an iron-fisted warden known as Walker, who operates a ghost prison. Referred to in most cases as the realm of the dead. Where the boundary lines that seperate the world of the dead and the realm of the living are parted by the thinnest of threads and where the laws of time fall in and out of alignment. You would prefer spending half en eternity to find your way through the countless doors that litter this realm with the slight chance of finding your way to freedom than crossing paths with the warden.
A broad city that is under the constant torment of Lucius Heinous the Seventh. A man who had elected himself as the ruler, mayor, judge and jury of Miseryville and owns the largest company in the Underworld, Misery Inc. whose main duty is to cause misfortune to all the city's residents. Lucius with the help of his lovely evil genius wife Heloise export many of their torture machines to other realms within the Underworld to cause more torment for everyone, regardless if they deserve it or not. Why demon would want to live in a realm of torrment is a question that they often ask themselves.
A mysterious realm existing in the Underworld that acts like a giant vault for every organism ever. Bill Cipher along with several other demons are the only inhabitants that live here and have access to the memories of anyone that has ever been on the surface, including those of the other overlords. Once someone enters the mindscape they mind find themselves in a mysterious black-and-white version of their own mindscape where they can delve deep into their own memories.
Realm of Malebolgia
An ancient desolated realm where Malebolgia's orders are supreme. In the bloom of the Underworld it was one of the most infamous realms around, being the place where the Phlebiac Brothers resided. It has been noted that Malebolgia is constantly at war with the rulers of the other spheres of Hell. But the realm descended as the 8th circle of Hell and was kicked out the overlord council for being nothing worthy. The Phlebiac Brothers were slain and Malebolgia lost the powers he once had.
Traversing in the Underworld
- Some of the rulers, and even others, have the ability to traverse between the Underworld and the Surface by use of portals.
- These are Grim Reaper, HIM, Aku and Nergal.
- Through terms of a ritual one can traverse to and from the Nightosphere. One must draw a happy face (Phil Face) on a surface. Douse the face with some bug milk and chant, "Maloso vobiscum et cum spiritum!"
- A Ghost Portal is a means of going back and forth between the Ghost Zone and the Surface.