The Lower Elements is a fictional underground city within the Artemis Fowl world. The term refers to all areas underground that the humans (referred to as "Mud Men" by the fairies) in general do not know about. The Lower Elements are where most, if not all, fairies and other non-human beings in the series live.
In the fictional setting of the story, fairies and their other magical cousins used to live above ground but when the human race evolved, the fairies were forced to move into more secluded places then, finally, underground. Fairies are peace loving and were not eager to go to war against the 'Mud Men'(Humans) The LEPrecons have many entrances to the Lower Elements. They cannot enter human homes without permission or they will be overcome with a wave of nausea (This was undone by the warlock N°1 sometime between The Lost Colony and The Time Paradox).
The fairies are a very advanced set of races with a recorded history and society far older than human history, and thanks to the technological head-start, The Lower Elements are equipped with extremely sophisticated technology, vastly superior to that of the human race. The Lower Elements are referred to as having artificial sunlight.
Despite the luxuries they have available to them in The Lower Elements, including natural hot water ( due to proximity to the Earth's core), sophisticated means of transportation and of course, impressive technology, the fairies' lives seem to revolve around the surface of the Earth and human society. The only films fairy characters in the series are portrayed as watching are either made by humans or about humans, including "a human Western" which Grub Kelp views in The Opal Deception and a cinema movie about the fairies epic battle with the humans in The Lost Colony. At another point in The Opal Deception, Mulch Diggums remarks that fairies are "obsessed with Mud Men".
The Lower Elements are protected by a police force called the LEP (Lower Elements Police) which also seems to serve as a military as Briar Cudgeon and Opal Koboi plan to take over The Lower Elements by seizing control of the LEP in The Arctic Incident.
Reconnaissance officers are an important body in the LEP and are referred to as LEPrecons, a play on the word leprechaun.
The reconnaissance officers in the LEP are particularly fond of flying above ground on "recon" missions, especially the heroine of the series, Holly Short and her superior, the late Julius Root. Root at one point humorously reminds Holly that "there is life below ground you know."
Holly is contemptuous of The Lower Elements, referring to them as a "technologically advanced cave" and believing that the fairies deserve to live above ground.
A few characters are mentioned in Book 1 that seem to be on the Council: Vinyáya, Cahartez and Lope.
In the first book of the series, the power-hungry Briar Cudgeon is obsessed with ascending to The Council. When his plans are thwarted and he is found to be corrupt and thus demoted, he is left consumed with hatred and determined to get revenge. He plots a coup with the villainous Opal Koboi and later says to Foaly that if it weren't for him, Root, Holly and Artemis he would be Chairman, referring to himself as having been "The Council's golden boy."
Fairy society was once presided over by a monarchy, the first ruler of which was the Elfin King, Frond. Lily Frond, the beautiful Elf who represents the LEP is descended from Frond.
Opal Koboi is obsessed with becoming dictator of The Lower Elements and eventually the entire planet, desiring power not held "since the days of the monarchy."
The Council is also mentioned in the second Artemis Fowl book, when one of the Council members was helping to keep back the B'wa Kell while the other Council members were being protected.
Lower Elements Police
The LEP is made up of several different units, as with all police forces. Overall, their job is to maintain order and to prevent humans from getting word of their existence. They are also the closest thing the fairy People have to a dedicated military.
The ranks are in this order: Recruit, Private, Corporal, Lieutenant, Vice Captain, Captain, Major, Commander. There are three regional commanders and an eight-member Council which is in charge of the entire LEP.
The Lower Elements Police reconnaissance squad, better known as LEPrecon, is the celebrated stealth reconnaissance division of the Lower Elements Police (LEP). In the underground world of the fairies, most reconnaissance entails tracking down fairies who wander where they shouldn't, particularly away from the secret fairy civilization of The Lower Elements and onto the surface of the Earth.
The Reconnaissance and Retrieval Squads are the elite, 'SpecOps' division of the LEP.
Members of the squad are also called LEPrecons, or leprechauns, the name of which is a pun, and in the context of the books, this is where the term originated.
The Lower Elements Police retrieval team is better known as Retrieval. Retrieval's most elite unit is LEPretrieval One, led by decorated fairy, Commander Trouble Kelp, who appeared in book one as a Captain. It is said that every young fairy's dream is to join LEPretrieval One and don the stealth black jumpsuit. Highly trained as they were, the fairies were easily "removed" by Butler on their first encounter. Retrieval has made many appearances throughout the series. Their job is to use information from LEPrecon, perform mind wipes to humans who may have seen a fairy, retrieve rogue fairies, retrieve/destroy trolls who have made their way to the surface and other various tasks.
The Lower Elements Police traffic team, better known as LEPtraffic, is the traffic-policing division of the LEP. They patrol the streets and overlook road construction. Traffic police are often referred to as "Wheelies" and are known to use magna-bikes and cruisers for transport. They wear a computerized suit which can display all common traffic signs as well as eight lines of text comparable to a walking traffic road sign. The suit is also coded to the wearer's voice ensuring that should the wearer ask a driver to do something, it would also be displayed as text across the wearer's chest. Every corporal who has signed up to the Lower Elements Police Academy must serve a period of time in LEPtraffic before being allowed to enter a specialized department, such as LEPrecon.
The LEPmarine is a section of LEP that patrols the Atlantic Ocean, cleaning up after people and protecting endangered species. Holly Short's mother, Coral Short, had been a doctor with LEPmarine until being fatally injured when a tanker her group was shadowing accidentally doused their submarine with radioactive waste.
Mentioned once in the first book, the Telekinetic Division was called to fix the wall of the restaurant that a Troll, which Captain Holly Short fought with, severely damaged. Apparently the Division consists of fairies who are trained in more advanced magic (i.e. telekinesis, mind wiping) than the average LEP officer. They seem to be used mainly in quick repairs and construction.
Internal Affairs is a section of the LEP that deals with rogue LEP operatives. It is mentioned in The Opal Deception (Book 4) when it is believed that Holly Short is responsible for the murder of Julius Root. Ark Sool commanded this before getting promoted to LEPrecon Commander in Opal Deception after Root's death.
The Kraken watch are a small but dedicated section of LEP, although not many krakens exist in the world. Holly Short is assigned to it at the start of The Time Paradox (book 6), as a typical "First day back on the job" assignment.
Section Eight is a covert intelligence-gathering division of the Lower Elements Police, similar to the CIA or MI6. Its foremost purpose is intelligence on the location, rehabilitation, and general welfare of all demons that materialize from Limbo. It is presumably named for the fact that Demons are "the eighth family of the fairy People".
The LEP Section Eight is introduced in Artemis Fowl: The Lost Colony. Wing Commander Vinyáya is the Council's chairwoman to Section Eight, and its technical director position has just been filled by the centaur Foaly. Holly Short is recruited into the organization as a Captain after leaving her own small private investigation firm. Vinyáya reveals the Section's original founder to be the late Council Chairman Nan Burdeh, who bequeathed her enormous fortune to Section Eight, allowing the organisation to purchase state of the art equipment and offer "excellent overtime and medical insurance".
The expression appears in the first book, but only in the US military sense of the term Section 8, meaning crazy, as Holly says she's gone "Section 8" risking her life for a human fighting a troll.
The only locations in The Lower Elements seen so far in the series, apart from the various chutes and tunnels, are the cities of Haven and Atlantis respectively.
Haven City appears to be the capital city of The Lower Elements and as such, most fairies in the Artemis Fowl series reside there. Major government buildings are found here. It is home to the headquarters of the LEP, and The Council, the main governing body of The Lower Elements. It is one of the most populated cities in the lower elements and is widely regarded by fairies to be the greatest metropolis since the Old Atlantis (now gone) but to human standards, it is little more than a village (albeit a very high-tech one) with less than 10,000 inhabitants . Its main road network consists of tunnels and several chutes, like E1 and E37. The transportation system is a magnastrip, which is very efficient. Blast walls also protect the city in emergencies.
Very little is known about Atlantis, except it is under the sea, it is smaller than Haven and its residents use gills to breathe. Mulch Diggums escaped from a prison shuttle bound for Atlantis, also conveniently incapacitating the prison shuttle.
In The Opal Deception, Atlantis is stated to be built over the ruins of the old Atlantis which was bigger than the current one.
More will probably be revealed in book 7 in the series, Artemis Fowl: The Atlantis Complex.