The Underground Kingdom is located in the cave system under Canterlot and is ruled over by Crosis.
Description
Crosis
The Underground Kingdom was founded by Crosis when he fled Canterlot. He had gathered a few friends and follows but was ultimately sealed away in a stone when he went above ground. A group of his followers brought the stone under ground and set up a cult around him. Slowly overtime the ponies started to build homes for themselves that would eventually turn into a kingdom. The Underground Kingdom is located in the cave system under Canterlot and is far more technologically advance than the rest of Equestria. It is home to the Steampunk Ponies and Cyberpunk Ponies. There are several cities located in thge many chambers under ground, the largest houses the tallest buildings and the castle where the King resides.
Chambers that are too small for living space, are used for other task, such as factories or mining. There are a few chambers used for farming the local mushrooms and fungi that the Steampunk ponies enjoy as food. The buildings are mostly made of stone with metal piles and tubes imbedded into the walls. There is also an underwater river that the Kingdom uses to water their crops and were drinking, however the Kingdom has also tapped into the water table with wells and pumps. The Kingdom is also littered with machine parts and even unfinished robots. The Kingdom is protected by the guard, and Steam Guard, a ground of robots that stand around the Kingdom's outer walls keeping watch for danger.
Skinwalker
There are several large building that resemble castles dotted throughout the Kingdom. The largest is known as the Palace where the King lives. Unlike other places of royalty, Crosis allows regular people come and go from his Palace, however some places are off limits. The Palace served as a Temple before Crosis was freed and was where his stone was located and still is.
A group of changelings were accepted into the Kingdom, and Crosis eventually found himself a mate in the form of a Changeling King named Skinwalker. The two co-rule over the Kindgom together and now have a daughter named Princess Butterfly Kisses. Since thwen Crosis have been calling himself "Queen" of the Underground Kingdom. When one of the Kings leaves the Kingdom, the remaining king rules over the Kingdom alone until their partners return.
Inhabitants
The Underground Kingdom is home to the Steampunk ponies, many who are cyborgs or simply enjoy wearing machinery on their bodies. These ponies where odd and creative outfits infusing fashion with machinery. Some ponies even infuse their own bodies with cyborg parts, weather to fix an injury or just for appearance. Steampunk ponies are far more open minded than the ponies that live above ground. Steampunk Ponies are made up of the usually three breeds of of ponies Earth Pony, Pegasus and Unicorn. Besides the pony population, the Underground Kingdom is also homes to Chiropractors, Diamond Dogs, Mole Men and other underground creatures including a dragon.
The Underground Kingdom is govern by their King Crosis The Purger, and his council, complete with a mage. The city is kept in order, more so out of the Steampunk ponies' kindness than by their gaurds. The King is protected by an elite ground of guards called the Shadowmares.
There is a Mage's Castle were new magic and new ways to use it is explored. The Castle allows some magic forbidden or shun by the rest of Equestria to be practice here.
Culture
The Steampunk ponies of course enjoy anything technological. They adorn themselves with machinary, top hats, watches and dresses. Seeing any one walking around without some kind of technology on their person is rare. The most common form of music is Techno, Hard Style, Punk Rock, Electria and sometimes Goth and Emo but those are a little on the rare side.
Most inhabitants enjoy learning and discovery. There are many factories and field of science for the residents to explore and work in. Mots of the common ponies work in the factories or around the cities, or on the farms. Common jobs include, Farmer, Engineer, Technician, Teacher, Shop Keeper, Factory Worker and Guard. More elaborate jobs are Scientist, Musician and Mage.
Magic is still used even thought The Underground Kingdom is more about technology than the old ways. Exploring new magic in new ways is common in the Mages' Castle.
The Steampunk Ponies hardly leave the Kingdom, they are self sufficient and don't need supplies from the surface. However some farms are located above ground and appear to be normal farms to the average pony. There are few reasons for most ponies to leave the gates, usually ponies leave to find odd objects to add to their collection. Steampunk Ponies are known for being collectors and in some cases as "pack-rats."
The Cyberponies and Steamponies believe and worship the twin Goddesses Cyber and Steam. Cyber governs the advancement in computers and the cybernetics while her sister Steam governs the technology and advancement in machinery.
Layout
Within the Underground Kindgom, the chambers of the cave system are refered to as Districts when relating to areas of a curtain kind of pony is located, Steam or Cyber.
Metropia - Captial of the Underground Kingdom, locations of the Castle
Clockworks - Steampony city
Decker - a city of Cyberponies
Neonlight - a city of Cyberponies
Industia - A city of Cyberponies
Trivia
- The Underground Kingdom was actually thought up during the events of season 1 of My Little Pony: Friendship if Magic, before it was reveal in season 2 that there were actually caves under Canterlot.
- The Underground Kingdom resembles a Dwemer Ruins in Elder Scroll V: Skyrim.