Gargauth

Gargauth, originally known as Gargoth and sometimes called Astaroth or Gormauth Souldrinker, was a former archdevil and the Faerunian demigod of betrayal and political corruption. Wandering the Material Plane after being cast from Hell for reasons unknown, the utterly depraved devil was dedicated to infecting the Realms with his own brand of corruption and cruelty. An incarnation of evil most rotten, Gargauth embodied the inevitable moral decay that followed both the victories won by evil means, and the selfish, greedy, and ambitious entities (both leaders and groups) that achieved them.

"My, how the mighty have fallen!"

- The ironic words of Sylvira Savikas

Description
Gargauth's natural appearance was that of a terrible, evil apparition. He was a clawed and fanged monster with jagged shards and horns that jutted from his face and back, and flesh as rotten and warped as his clothing. However, Gargauth's real form only became apparent after he spent some time in an area, such as a town or a specific region. After about one to four months, he would begin twisting back to normal, but his enchanting aura kept those who met him in his thrall even after the physical transformation. Typically only those who met him after the reversion would be aware of his true nature.

Gargauth often appeared as an tall, mustached man of handsome and noble visage, his exact age indeterminable, but his maturity clear. He spoke with a voice that was deep and low, yet whispering and hollow, and at times even reptilian. Sometimes he was known to disguise himself as a mundane trader or old pilgrim, and in the past he had taken on the forms of various races, but only rarely did he appear as female. He often wore swash-topped boots, jerkins with slit and capaciously puffed sleeves, velvet-lined cloaks and other such intricate finery accessorized with pendants, cloak pins, buckle ornaments, and huge, sparkling knuckle rings.

Personality
Gargauth was a dangerous and thoroughly wicked being, the guise of civil compassion he wore at first only making the cruelty more horrible. He came off as a personable, reasonable and sagacious in most of his encounters, with nearly all he came across viewing him as the wittiest and wisest being they ever met. Even compared to the Lords of the Nine, he was a master strategist, a rival to even Asmodeus in terms of wiliness and guile. Despite his charming façade of intellectual sophistication however, Gargauth's true nature, that of a being so foul that supposedly even his fellow archdevils were repulsed, always revealed itself eventually.

Gargauth also had the most self-control of all the devils, and on top of believing himself to be one of, if not the, smartest of archdevils, he was certain he was the least impulsive. Part of Gargauth's self-control laid in the fact that he also had the strongest sense of humor out of all devilkind; this capacity for amusement moderated his emotional responses, allowing him to react with an even-temper even when Asmodeus would fly into a rage. A particular joy of the manipulative demigod was holding to the letter rather than the spirit of his agreements, forging pacts and poorly-worded contracts and binding others to them before relishing in the betrayal when he twisted them to serve his own ends.

Gargauth revealed nothing of his true personal feelings to anyone under any circumstances, and in general preferred to work in the shadows or in disguise with no one the wiser. When he spoke, it was always with a sense of contemplativeness and dispassionate detachment. He often pretended to hold certain beliefs and emotions so as to mislead and manipulate his current audience and was known to drop subtle hints to get others to reach false conclusions. So skilled was he in the art of intrigue that he could elicit obedience from creatures as unbelievably vain as blue dragons.

Powers
Gargauth's enspelling aura worked similarly to a permanent mass charm spell, and was both difficult to resist and impossible to dispel. Gargauth himself was immune to all forms of enchantment, as well as sleeping and holding spells, poisons (including toxic gases and venoms), and fire both magical and mundane. He could also breathe underwater and had resistance to the cold.

An avatar of Gargauth had a wide range of spell-like abilities at its disposal in addition to those available to nearly all baatezu. They could cast spells like pyrotechnics, produce flame, wall of fire, and fireball, as well as ice storm. They could also cast eyebite, shapechange, charm monster, and, with some limitations, grant the wishes of others every ten minutes. He showed a preference for abjuration, enchantment, evocation, and transmutation spells.

He had other strange abilities as well; his gaze caused confusion, he could breathe out a long,  wide cone of fear every two minutes, and he could choose to create either a symbol of pain or symbol of insanity once per day. Gargauth's avatar could, at will, surround itself in a caustic cloud of sulfurous fire that could knock out anyone within a radius and would ignite anything combustible.

Metal
One of Gargauth's noticeable abilities was his power to transmute nearly any metal into gold simply by touching it. The gold created by the process was pure and conformed to the pre-existing shape of whatever was transformed, but was brittle and soft, and so would twist and crumble if too much pressure was put on it. Though there was no limit to the volume he could transform, but only 600 gold pieces worth of material could be altered each day. The transmutation didn't repair items that were already broken and left the transformed object bereft of magic if it didn't resist the process, although powerful artifacts were immune. He could choose to morph only the object he was touching or other metal objects attached to it even if they were different metals and the power didn't work if he was somehow magically controlled.

Some stories had Gargauth change raw ore into gold but some reports stated the object had to be processed, however crudely, for him to change it. Similarly, it was unclear if he had to use his gold-changing power all at once each day or if it was an overall limit, and he could keep changing separate tools so long as he didn't go over it.

The one metal Gargauth couldn't alter was silver, for which he had a notably crippling weakness. Normally he regenerated over time, but mere contact with silver was incredibly dangerous. At one point someone hurled a bag of silver coins at him and nearly killed him, so he always protected himself with a protection from normal missiles spell before entering battle whenever possible. Any silver weapon he came across he disposed of if he couldn't destroy it to prevent it from being used against him.

Baatezu
The one spell school that Gargauth couldn't cast from was conjuration. He couldn't summon other devils and in turn he couldn't be summoned by them or spells that summoned them, though magic that compelled devils to serve could be used on him if encountered. It was believed by sages that he had a unique power, one that caused some to suspect he was no longer a devil, the ability to plane shift once every nine days anywhere in the multiverse. The power that Gargauth kept absolutely secret however, was incredibly dangerous. So long as a baatezu was physically present in the Realms, having used a magic gate for example instead of being summoned, he could fully absorb their power by slaying them. It was through this ability that he managed to achieve apotheosis and, if he had his way, would rise to even greater heights.

Possessions
Though Gargauth was capable of fighting with his fists, he usually carried enchanted throwing daggers in his sleeves. It was said he carried only around four to six, but other reports claimed he had an infinite amount at his disposal, though notably they would vanish within seconds of striking their target when hurled. He was proficient in the daggers, able to juggle them with the skill and flair of a showman. He could use almost any melee weapon skillfully, and on occasion made use of a rapier. He often carried venomous snakes wrapped around his arms, that he would use as weapons in combat.

Gargauth had penned a complete chronicle of his journeys as an emissary of the archdevils, a tome older than Mulhorand pyramids and with pages that had started yellowing long before the crowning of the first Cormyrian king. In it were lines of cramped, magical text, cryptic writings that alluded to primordial battles between strange cosmic beings, possibly greater than even Ao, and supposedly ancient, unspeakable magics and creatures of unimaginable vileness. The original copy existed in Oghma's Outlandian library, and though other copies possibly existed, it would be perfectly in character for Gargauth to have cursed some or all with a myriad of malignant hexes.

One of Gargauth's most useful items was what became known as the Shield of the Hidden Lord. The shield was made from pure mithral and inlaid with hundreds of tiny jewels worth several small kingdoms. Despite having celestial origin, Gargauth's vile influence warped the shield into an artifact of his own so that the celestial designs twisted into a snarling, fiendish face that sometimes moved in disturbing ways. No legnds even hinted of the shield's existence, and it was found in an ancient tomb in the Fields of the Dead. Gargauth could communicate to others through the shield and vice versa, and he used it to manipulate the Knights of the Shield's secret council. However, Gargauth somehow became fully trapped in the shield, and so was forced to seek further power and influence from within it while trying to escape.

Realm
Gargauth could freely wander the planes with the exceptions of the Upper planes, and the Nine Hells, on threat of permanent death if he ever returned home. In a sense, his homeplane was the Prime Material Plane, since that was where he expended most of his effort, particularly on Toril. He had no known lair, though he likely had several hidden by illusions, and was typically on the move.

Activities
Despite his evil machinations, Gargauth was known to take time to amuse himself, such as by casting snakes at sleeping individuals.

Gargauth's short-term desire was increasing his worshiper base and the population of his religion so as to increase his power and standing among the gods. The specifics of his master plan weren't known, but in the long-term he sought to enslave all of western Faerun (including the Lands of Intrigue and the Western Heartlands) under his diabolical rule. This was thought by some of his own worshipers to all be part of an even grander scheme; they believed that Gargauth's true intent was to turn all of the Forgotten Realms into his unholy kingdom before transporting it into Baator, where upon it would become the basis for his own tenth layer of Hell.

Unfortunately for Gargauth, he had become trapped in the shield he once used as communication device, and so had to try and seek divinity from within his prison. His corrupting nature in his bound state, despite being reduced to a pit fiend in actual form, was so great that he could cause moral decay in the entire city he was in, and for decades he had contributed for the rampant greed and hate in the hearts of Baldur's Gate's residents. Though he greatly desired freedom, he didn't know how to obtain it and couldn't move while in the shield. His plan to escape was to find some expedient means by which to enter the Nine Hells, convinced that the shield would be weakened enough for him to do so.

Relationships
Gargauth was a loner by nature, and despite his methods and goals being traditionally diabolical, he never openly cooperated with devils or their agents. His few servants consisted of undead and creatures that he could control using charm monster, with him showing a preference for snakes and blue dragons. He customarily employed an adult (or older) blue dragon as his steed, and had grown quite fond of a particular great wyrm named Rathguul that he often engaged with in games of riddles, and that he had bound by ancient contract. He often had one or more giant poisonous snakes, such as pit vipers, wrapped around his arms. For the longest time, he even had a marilith consort known as Charsultketh, who he had planned to make his enforcer when he took direct control of the Knights of the Shield. Some tieflings of House Gralhund could trace their ancestry back to the Exile.

Gargauth counted as his foes a litany of evil gods, including the Dark Deities (Bane, Bhaal, Loviatar, and Talona). He was also opposed by Bane's son Iyachtu Xvim, as well as Cyric and Shar. He was one of the few foes of Dugmaren Brightmantle, explorative and knowledge-seeking member of the Morndinsamman, since the Hidden Lord embodied everything corrupting and malicious about the search for knowledge. He posed a particular threat to Siamorphe, demigoddess of rightful rulership for the benefit of the people, as he had interest in corrupting the sort of souls she held up as virtuous exemplars. Gargauth also opposed Ghaunadaur, who long ago had stolen the aspect of Gormauth Souldrinker from him and completely subsumed it.

Archdevils
Gargauth was once one of the Lords of the Nine, but was banished for unknown reasons, potentially because he was considered despicable even by their standards. Regardless of the reason, he didn't seem to bear any grudge against them, and had seemingly been serving them for eons as an ambassador and representative for eons. He was something of a watchdog, working to further their common interests on the Material Plane while keeping tabs on the activities and loyalties of devils and servants there.

That wasn't to say that Gargauth was loyal to them, for Gargauth was loyal only to himself, nor did he acknowledge anyone as his superiors. Gargauth was lawful evil in the sense that he made the laws, and since he believed he outranked everyone in Hell's hierarchy in terms of strength and intellect, he was of the mind that he was free to choose his own path independent of them. For their part, the archdevils would likely ally to have him destroyed if they learnt of his power to absorb devils as a pre-emptive move to protect themselves.

Despite his banishment from Hell, Gargauth would gladly replace an archdevil like Zariel as Lord of Avernus after having been diminished in power, and Zariel in turn would order him destroyed if given the chance. Gargauth was known to respect Alastor the Grim, Asmodeus's executioner and the greatest pit fiend of all, Mephistopheles, the Lord of Cania, and Bifrons, Mephisto's philosopher duke and commander, though only Alastor was perceived as anything approaching an equal. He saw some of himself in Mephistopheles, viewing the Cold Lord as a young, inexperienced, and impulsive version of him. Gargauth's ally and purportedly his closest friend was Beherit (also known as Lucifer), but he had been killed by Asmodeus.

Despite this legend, Gargauth maintained close ties with Asmodeus, and some devils, notably Mephistopheles and Asmodeus's chancellor Adramalech, believed that the two were staunch allies as close as friends as devils ever were. Asmodeus was the only devil besides Alastor who he perceived as a relative equal, and in his mind was the most capable archdevil. Gargauth had never supported any other archdevils bid to depose the Dark Lord despite being continually sought after by ambitious dukes for his great personal power, bids that always ended in Asmodeus eventually knowing what happened. Gargauth was once a power in Hell second only to Asmodeus, and if he decided he wanted the Overlord's throne rather than to forge his own path, Asmodeus's days could very well be numbered.

Worshipers
Few individuals, in the Realms and otherwise, knew of Gargauth, and typically those that did never even spoke his name, let alone worship him, out of fear that he might come to visit them. Despite this, a small number of mortals as ambitious as they were foolish turned to the Hidden Lord for aid, willing to deal with the devil to achieve their dreams of conquest and power before later finding his price too dear pay. The few beings that knowingly worshiped Gargauth included a small fraction of Dragon Cultists, malaugryms, and Thayans, though he wasn't a major god in the lattermost's culture.



Dogma
The core tenant of Gargauth's faith was that the meaning of life was to acquire power. Civilization was a thin cover over everyone's basic wants, for all beings acted selfishly at all times, some simply disguising their inherent greed with sanctimonious philosophizing and utterly hypocritical, "high" moral principles. In order to survive and prosper, one had to recognize this and concentrate fully on pursuing power, using charming words or cutting daggers as appropriate, although when in doubt, the safest route to power was the ruthless use of pre-existing power. The politics of power strictly regimented the lives of all beings, and trying to avoid the game would leave the powerless ground into the dust of history beneath the bootheels of the more powerful. Sitting on the throne was not the same thing, and was in fact less important, then being the one holding power, who could very well be behind the throne.

The letter of all agreements and the rules established by those in power were to be obeyed, his priests believing that Gargauth enforced such arrangements and would bring down divine wrath on those who broke them. However, it was both acceptable and encouraged to twist the spirits of contracts and strictures to maximize one's own gains.

Church
Gargauth's clergy typically kept their faith a secret, although there were some significant exceptions. The entire clergy was regimented in a strict hierarchy with designated titles corresponding to rank. Novice Gargauthans were called Supplicants, while higher-ranking officials were called "Lords of the Pit". In ascending order, the clergy ranks were "Lord of the First Pit", "Lord of the Second Pit", and so on until one got to the High Priests that were the "Lords of the Ninth Pit". Higher-ranking priests often had individual titles, typically including variants of the true names of at least one baatezu Gargauth had previously destroyed. His clerics sought positions of power, to integrate those positions into the shadowy hierarchy of the faith, and to increase both their power and the church's (and by extension Gargauth's power).

It was the duty of Gargauth's clerics to be his eyes and ears throughout the Realms, and to try and corrupt its powerful individuals and community leaders and bind them in strict contracts that favored him. However, Gargauth's focus was less on diametrically opposed factions, such as the faiths of Lathander and Tyr, as it was on potential rival religions. Rather than waste effort fighting the forces of good, his priests were under orders to undermine the followers of gods like the Dark Deities in order to steal them away and gain more like-minded converts first. Gargauth's clergy was split relatively equally between ordinary clerics, who primarily worshiped him, and specialty priests known as malefactors, who worshiped Gargauth alone, although the balance was slowly shifting towards the latter since Gargauth felt they benefitted him more. All specialty priests knew other languages and had fine etiquette skills but all Gargauthans, specialty or not, had proficient knowledge of the Realms' religions.

Gargauth offered his specialty priests the powers of persuasion, giving them access to spells like enthrall, charm monster, command, and dominate person. However, the more long-term loyalty they showed Gargauth, the greater their physical corruption became. These changes imperceptibly hardened the skin and skeletons of the subjects, and included frightening physical anomalies, such as hunchbacks, reddish eyes, slit pupils, or claw-like hands. Many Gargauthans also trained as sorcerers.

Orders
Gargauth's influence was often so indirect that the members (and sometimes even leaders) of the organizations he sponsored didn't normal know he was their divine patron. None of the handful of cults, secret fellowships, lost wizard circles, or knighthoods he supported were dedicated to his name. The most prominent organization following him, one he practically founded, were the Knights of the Shield. As was typical, a majority of "members" didn't know anything about Gargauth's influence, with somewhere between 75-80% of them just being agents of actual members. Of these 60-100 nobles and merchants, most saw the organization merely as a convenient family tradition, a secretive way to share insider information for financial and political benefit.

Many members legitimate, if self-interested, and only a few actively involved themselves with the organization to gain power and wealth, but only the Shield Council, an inner cabal few else knew about, had any clue about its true purpose. Of the seven members, four were simply senior knights that had served themselves and the organization at the expense of ethics, and only the three highest members served the Knights specifically for Gargauth's ends. The Shield Council believed Gargauth was an intelligence within the Shield of the Hidden Lord and, before it was lost, consulted it like one would a tarot deck, relying on its cryptic, but always correct advice, when it deigned to speak.

Rituals
Clerics of Gargauth prayed for spells at dusk, for it symbolized the beginning of the day's corruption by the night. On the eve of the Feast of the Moon, they engaged in a personal ritual called "The Binding", where each priest renewed their eternal contract with the devil. In return for increased power, the priest made personal sacrifices of their own money, hoarded information and even blood, gave him magical tribute and casted spells unique to his faith, and pledged absolute fealty to the Hidden Lord. Each "agreement", was marked with a Blood Contract consecrated in Gargauth's name.

Every Midwinter Night, his clergy performed the "Unveiling", a horrific ceremony thought to involve several grisly sacrifices. The celebration heralded Gargauth's imminent unveiling, revealing the Lord Who Watches to be the Lord of All. The church believed that when this unholy rapture truly began, Gargauth would seize the realms as his own and transport it into Baator.

For formal rites, Gargauthan priests wore blood-red robes lined with ermine. Junior clergymen donned flesh-colored skullcaps with a broken horn studded above the brow, while seniors wore or held distorted masks, painted or enameled in bright, gaudy pigments, carved to resembled various gargoylish baatezu. They carried Gargauth's symbol in the form of a necklace with a broken horn somewhere in the design, such as one set with the two halves.

However, the Gargauthan clergy saw clothes as tools, the careful selection of which could assist in deception, or at least temporarily calm an enemy's suspicions. Priests would disguise themselves as sages, pilgrims, or even swashbucklers, but were unwilling to risk being completely unprotected at any point. All kept daggers on them at all times and were fond of hidden ones, as well as poison-concealing adornments, lightweight/easily hidden armor, and protective magic items.

Temples
Gargauth had little in the way of actual temples dedicated to him, but the few he did have were usually beneath large cities and accessible through deep pits. Sulfurous incense, burning braziers, and fire pits smoldered throughout the underground complexes, the walls in such places lined with depictions of Hell and with huge, brazen altars serving as the focal points of the sanctuaries. Baldur's Gate, Bezantur, Laothkund, Myratma, Sheirtalar, Teziir, and Waterdeep had hidden temples of the Hidden Lord beneath the streets, and dozens of other were said to be scattered throughout the Realms. The first true temple of Gargauth was said to have been made by the former Nar wizard Goorgian, who, along with his followers, formed the Order of Twilight.

One of the most notable centers of worship for Gargauth however, was the Dark Pit of Maleficence, a vast temple constructed beneath the ruins of Peleveria fifty years after it was destroyed. Supposedly built at the site of Gargauth's first appearance in Faerun, the temple was built in a pit of incredible depth rumored to be linked to Hell itself. By going through a large cavern tunneled into the Landrise (formerly having served as the Peleverian granary) one could access the temple, which itself was inside a cavern intertwined and between long stalactites and stalagmites. Over 250 worshipers and 100 actual priests tended to great farms of fungus and Deep rothé herds (some tainted by Gargauth) kept in the surrounding caverns. Many nomadic tribes in the area around the pit had fallen under the fell influence of the priests, and served them as scouts and mercenaries in the surrounding region.

Other Manifestations
Gargauth rarely operated through servant creatures, though it was believed that simpathetic flocks, thick swarms of poisonous insects, or dense clusters of snakes passing through a region were ill omens foreshadowing his impending approach. His influence sometimes manifested as a solitary horn growing from an animal's head, an animal that would become increasingly malicious and more easily agitated. The curved, bony protrusion was a dangerous weapon if the animal charged, but it fell off and broke in two after about ten days, with the animal would become sickly and perishing shortly after. If both were blessed, the horn pieces could be a powerful boon, warding an approximately radius from where the spell was cast from Gargauth and his servitors for a year. However, if a Gargauthan obtained the pieces, they could use them as major component in horrible spells unique to the Lord Who Watches.

Gargauth was also known to manifest as a wavering, amber light to anyone that called for his help, the foul radiance serving to seal any deal between Gargauth and the mortal. Tainted with an aura of utmost evil, accepting its aid would only be the start of a series of spiritual corruptions.

History
Gargauth was an unimaginably ancient entity who, before his banishment, served Asmodeus as Hell's treasurer. In the early days of the Blood War, a tanar'ri demon lord named Astaroth infiltrated the legions of Hell, and managed to rise to the rank Gargauth once occupied (although it was unclear if this was before or after Gargauth's exile). Gargauth managed to expose the deceptions of Diabolus, the name the demon had acquired for his insinuation, but not before his spying had caused incalculable harm to the infernal side of the war, preventing Hell from winning a decisive victory against the Abyss.

Astaroth fled to the Abyss to prepare for the inevitable counterstrike from the archdevils and so began cultivating cults on countless mortal worlds by way of his precognitive powers. Unfortunately, his prophetic prowess didn't forewarn him of Gargauth, who during his travels as an exile had been commanded by Asmodeus to kill the sneaking demon. The two had a terrific battle, but despite attempts to become a god, which seemed to have worked to some degree, Astaroth was slain. Gargauth claimed Astaroth's name and his mantle of divinity, appropriating the worship of his few surviving cultists in Faerun under the demon's name and thus giving Gargauth his first taste of godhood. Even millennia later, Astaroth's form was trapped eternally regenerating (due to a deal made with Ahazu) while being burnt away by the hellfire Gargauth sparked.

Faerun
Gargauth's Shield of the Hidden Lord had appeared in the Realms during 889 DR when Duke Tithkar Illehhune joined the secret society of the Knights of the Shield. However, his believed first appearance in the Realms was in the Year of Awakening in 1001 DR, when he had been trapped within a Peleveran pit, unable to escape. During that time, Tuelhalva Drakewings, a member of a Banite sect of the Cult of the Dragon, had been sent to investigate reports of an ancient undead wyrm deep within the catacombs of the capital city of Peleveria. From his seemingly bottomless pit, Gargauth promised him absolute power, inspiring Tuelhalva to break free of his cult and break the ancient wards keeping Garguath trapped.

Tuelhalva prepared the eldritch, powerful magics to free Gargauth for seventeen years, and with the final incantation uttered, Gargauth rose from the pit and gave Tuelhalva an army of devils to do his bidding. But while Tuelhalva conquered Peleveran within a fortnight, Gargauth had flown north to the sect Tuelhalva had abandoned, telling them of Tuelhalva's actions while also claiming the archmage had destroyed an ancient undead dragon king he had found. The enraged cultists had 21 of their mages call forth a flight of dragons and dracoliches to annihilate the traitor, a Rage of Dragons descending on Peleveran within a month of the new lord's coronation. By the end of the battle, Tuelhalva, Algashon (the cult leader), and all of Peleveran was destroyed, while Gargauth—from the safety of some distant city—laughed diabolically at the foolishness of the power-blinded humans.

Gargauth had appeared within the Realms on many occasions, typically when requested by some dire cult or being of great evil. The followers of Bane once asked for the assistance of the "wild baatezu" in attacking the Sign of the Silver Harp, an inn on the edge of the Tunlands. The Silver Harp, a goodly organization that sought to bring balance between nature and civilization, was a common Harper destination after it had been refounded in the Year of the Wandering Wyvern circa 1022 DR. The Banite attack (sometime in the century after the founding) went horribly however, as Elminster had laid a series of powerful arcane traps in the location, forcing Gargauth to flee.

Godhood
Sometime after that battle however, Gargauth managed to reach the status of demigod, the culmination of several centuries worth of effort increasing his cult following and absorbing the essences of baatezu physically stranded in the Realms. His cult blossomed even more during the Harpstar Wars (beginning in 1182 DR and ending in 1222 DR), when the Harpers were fighting off the sinister shapeshifters known as the malaugryms. Since the attention of the organization was elsewhere, his followers were able to climb to power in many cities and regions, nearly allowing him to achieve lesser god status before the Dark Deities aligned to crush his followers and stop such an occurrence.

Gargauth's new plan had been to rebuild his worshiper base and recover his lost dominion, specifically by finding out how Toril was sealed off from the planes during the Time of Troubles. He had been researching the ruins of the Imaskari empire, the wizards of which managed to partially prevent the Mulhorandi and Untheric pantheons from entering the Realms long ago, in the hopes that cutting off other divine beings from Faerun would grant him much divine power.

During the upheaval caused by the Spellplague however, Gargauth apparently lost his divinity, having become actually trapped within the Shield of the Hidden Lord. Gargauth was eventually sealed within a tomb underneath the city of Elturel before being stolen by the Vanthampur family. Eventually it made its way to Thavius Kreeg, who was working with the Vanthampurs to try and foster corruption in the city in order to drag the city into Hell. Gargauth (incorrectly) believed that he could escape the shield if brought to Hell, and prioritized his escape above reuniting the item with the Knights of the Shield, that were incessantly searching to reclaim it.

Rumors & Legends
For eons untold, Gargauth was little more than a legend, both in the Nine Hells and on the Material Plane. He had appeared (either by his usual name or under one of his many aliases) in a few of the fables of practically every race in the Realms, featuring in cautionary tales about the consequences of overwhelming pride, unending greed and gripping megalomania. For example in the dwarven tale known as The Legacy of Astaroth, he appeared at the gates of a dwarven hall as a dwarf minstrel. Under the name Astaroth, he used his showman tricks to enrapture the typically dour dwarves, his enchanting nature managing to bypass their typical suspicion. The dwarves invited him inside for an evening meal, which Astaroth graciously accepted, only for the dwarf king and his retainers to notice something strange.

Every piece of metal Astaroth touched turned to gold, but he seemed completely unaware of the effect. After finishing dinner, the dwarf king slyly took Astaroth on a tour of their subterranean city while encouraging him to touch every piece of metal the dwarves could find, even the veins of unmined iron. By the time Astaroth left the dwarves were incredibly wealthy, leading the king to rename the city the Hall of Pure Gold, but such affluence didn't last long. Before even 24 hours had passed, a horde of orcs and giants, who the dwarves had only barely managed to fight off in the past centuries, attacked. This would not be a particularly worse problem if not for the fact that their steel armor, weapon,  and defenses had all been turned into pliable gold, and so the fort fell within a fortnight, and all but one dwarf survived to tell the tale. From this tale came the dwarven expression "Gold makes one rich, but steel makes one richer".

Exile
Though his unwieldly malevolence was the typically cited reason, it wasn't actually known why Gargauth was casted from the Nine Hells. Some sages purported that he challenged Asmodeus and lost, and so was driven into exile, while others claimed that Beherit's destruction at Asmodeus's hands were what sparked his departure. Still others, however, believed that Gargauth left somewhat voluntary, his ejection from his home plane being part of a wider scheme for power. Asmodeus supposedly sent him to the Material Plane as a pit fiend to corrupt mortals, but it was thought that the devil had been striving for divine power since his banishment. Gargauth sought the strength and status of the divine beings, believing that ascension into the Faerunian pantheon to be the key to surpass his archdevil peers in power. Any or all reasons could be true, and Gargauth wasn't known to reveal his true feelings.