In a Norrathian age long past, when dragons ruled the lands, seas, and skies, an ancient race did spring forth from the will of an unknown god. They were a cunning and powerful race of beings, able to survive in a harsh world ruled by the scaled children of Veeshan. The true name of this extinct civilization has been lost to the mists of time, the evidence of their existence buried and all but destroyed by the elements and the forces of change.
The eldest of dragons sometimes whisper tales of this lost race of beings who were the first to stand against and slay the great children of Veeshan. They speak of them to their young, as a human mother would tell ghost stories to her child. The dragons whispered tales of a great kingdom of wicked yet noble beings that built cities from the bones and sinew of the slain children of Veeshan. This is one such tale, passed down to the scribes of New Tanaan many years past by the dragon sorcerer Ulvaxazoviak.
Many ages ago, in a time that only the spirits of the ancestor dragons can recall, a long dead ancient race, The Xulous they are called in the tales of my kind, did build upon the lands that would become Tunaria a great necropolis to house their dead kings. The crypts of the necropolis were fashioned from preserved remains of slain dragons and it was called Lxanvon, which means in the tongue of the Xulous, 'Kings Rest'.
As the necropolis filled with the dead Xulous royalty, honored and revered in death as much as in life, a festering evil began to take over in the lowest bowels of the crypts of the kings. The Xulous, through their adoration and reverence of their rotting kings, their defilement of the dead children of Veeshan, and their dependence on the deaths of dragons for the expansion of their kingdoms did unknowingly bring a powerful and ancient evil to Norrath. As years passed, the evil presence in the bowels of Lxanvon grew stronger, and there, within the rotting corpses of those ancient kings, Bertoxxulous was born. The royal priests of the Xulous kingdoms often journeyed from their ivory cities to Lxanvon on behalf of their people, to deliver offerings and praises to their dead kings. Bertoxxulous, donning the decaying bodies of the dead Xulous nobles, appeared before these royal priests demanding obedience, reverence, and sacrifices. Bertoxxulous deceived and corrupted the minds of the royal priests and their allegiance belonged to the Lord of Death and Decay above their living kings. Amidst these firsts priests of decay, one was held above the others, Ultor Szanvon the Putrid; he led the priests of decay in the spreading their dark doctrine. Ultor, an influential priest in service to the mightiest of the Xulous nobles schemed and murdered his way into the position of chief advisor to the living Xulous King. Ultor convinced Xulous King to visit the tombs of his ancestors, and there within the presence of Bertoxxulous' full might he performed a dark ritual, sacrificing the king in the bowels of the crypt. Through the dark ritual Ultor summoned twelve spirits of previous Xulous kings and bound them to his service.
The risen undead kings rose armies of the dead from the necropolis of Lxanvon and spread across the lands ravaging all in their path, and leaving only death and destruction in their wake. Those who were not destroyed by the weapons of the undead armies were killed slowly by a deadly plague, carried by the risen kings, and spread like wildfire amidst the Xulous. Their entire race succumbed to the pestilence and the Xulous were no more. Bertoxxulous, pleased and swollen with pride by his genocidal accomplishment called his minions back to the necropolis that had served as their resting place for so many years. The risen Xulous kings gathered in the bowels of their crypts as a great mist enveloped Lxanvon.
The ancient dragons watched from afar as the mists cleared, revealing only a barren and broken landscape where the necropolis had once lied. It is said that the necropolis of Lxanvon still exists in the Plane of Disease, unchanged from when the ancient dragons witnessed its vanishing from Norrath, and that the form Bertoxxulous favors when visiting Lxanvon is a twisted visage of the long dead race he destroyed, so many ages ago. 
Fabled PoP Lore- Part 9 & 10
The crypt was originally built upon Antonica in an age long past to house the dead kings of a long dead ancient race. That race called it Lxanvom that means in their tongue, 'Kings Rest'. As they filled it with their dead royalty a festering evil began to take over in the lower bowels of the crypt. Some scholars say this was the birth of Bertoxxulous, others claim that he has been around since time began and it was just the first ancient recording of his coming. However, his power within the crypt grew stronger as years passed. The time came when he made his presence known outside the crypt. At first he let only those within this ancient civilization who held the power of decay and waste dear to their hearts know of him. As these first priests of decay came to be one of their number was held above the others. His name was Ultor Szanvon the Putrid; he led the priests of decay in the spreading of their dark doctrine. Ultor was able to scheme and murder his way into the position of the chief advisor of the present king of this civilization. Once Ultor reached this position of power he tricked the king into coming into the crypt to visit the tombs of his ancestors. Within the crypt in the presence of Bertoxxulous' full might he performed a dark ritual sacrificing the king in the center of the crypt. Through this ritual he summoned twelve spirits of previous kings and bound them to his service. These creatures rampaged through the land causing death and destruction as they went. They were also carrying an extremely deadly plague. This plague spread like wildfire across the land wiping out the remnants of this ancient civilization.
Bertoxxulous took great pride in the fact that he had wiped out this civilization. He took his minions from the land and also summoned the entirety of the crypt to his home in the Plane of Disease. It is said that the form that Bertoxxulous favors when he visits the crypt is a twisted version of the long dead race he wiped out ages ago. 
Deep within the Crypt of Decay were the twelve burial chambers of the Ancient Kings. These twelve kings were Feig Glaemod, Xu Ezuqu, Kavilis Dri, Raddi Nroo, Wavadozzik Grequex, Zandal Bri, Akkapan Perin, Meedo Wrolo, Qezzin Adan, Pzo Wefian, and Bhaly Nestif. They were the first kings that had founded and ruled over the ancient civilization that had built the crypt originally. When Bertoxxulous' high priest, Ultor Szanvon, performed the dark summoning and sacrificed the current king of that civilization ages ago, the twelve spirits of the ancient kings were ripped out of there long peaceful rest and were forced to coalesce into the form of the twelve Heroes of Bertoxxulous.
Each of these heroes was given a unique form, except the four most ancient that received the same form. These heroes vary in powers and abilities, depending on which king's soul and form they received. Once the dark summoning was over and they were all in their given forms they were sent to complete the destruction of this ancient civilization.
Darwol was the last of the kings to receive his own private burial chamber. He was credited with leading his civilization into the final stages of a permanent golden age. When his soul was ripped from his peaceful rest, he was forced into the form of a ravenous rat creature. In the rat creature the soul became corrupted with malevolence and was known for its brute strength and temperament. He wielded a large cleaver known as Dark Corruption. (Actually drops “Darwol's Cleaver” 43/35 2hs, Devour Soul proc, unique graphic)
Feig was the eleventh king in the burial chamber. He was known to be a just and valorous king who was honored by his people with a holiday of his own. His soul was ripped forcefully from its rest and forced into that of a diseased creature. After leading the destruction of numerous cities and other lands he created a magical belt known as the Putrefied Belt of Death from the dead skin of his victims. (Actually drops: “Stitched Hide Pants of Fallen Foes” dru/mnk/bst legs)
Xhut was a sorcerer king that wielded powerful magic to aid and defend his people. He created many of his own spells during his reign and was loved by all. However when disturbed from his rest he was immediately joined with a powerful magic wielding undead creature. From there he used his powers of magic for necromancy and desecrated the very earth he walked on. He was credited with the creation of the Wrath of Souls. (Actually drops: “Xhut's Talisman”, Shd only, clicky item with Shroud of Hate)
Kavilis was a learned and intelligent king. Called the Scholar King by many during his reign, he led the people in the building of the first schools and universities in the land. When his soul was ripped out of his rest and forced into a foul creature it took the form of a twisted malevolent mosquito. He flew across the land spreading pestilence and corruption. It is rumored that his needle nose could be wielded as a fine rapier if the right craftsman is found. (Actually drops: “Kavilis' Mosquito Lance”, 35/25 2h pierce weapon)
Raddi was a famed warrior in his own right and knew no match in one on one battle. During a battle ages ago he led a small troop of his people and held off thousands of troops turning the tide of the war. His soul was forced into that of an undead knight. Given his immense skill with weapons he tore across the land leaving trails of blood wherever he went. He wields a one-handed blade known as Blood Defiance. (Actually drops: “Blood Defiance” (got it right!), 22/24 1hs, Shd only)
The seventh king to ever rule the kingdom, Wavadozzik is said to be by some the wisest king that has ever lived. Learned in the ways of priestly magic his kindness and wisdom was unheard of. When his soul was ripped from its rest it was put into an arachnid creature. He spread venomous poison across the land, driving those before him in fear and terror. The chitin of his hardened shell should make an excellent armor. (Actually drops: “Chitin Shoulders of Decay”, Plate class shoulders)
Zandal was a noble king filled with good intentions. He led his people to a new pinnacle in life standards. When his soul was ripped from its rest it was forced into a fly creature. It wandered the land feasting on the carrion of the dead as it spread its deadly plague. Its shimmering wings could perhaps be used to craft a shield. (Actually drops: “Drape of Wings”, caster shoulders)
Akkapan was better known as The Nimble for his quick feet and quicker wit. A rogue at heart, he was one of the most loved by his people. His soul was ripped out of its resting place and placed into that of a quick-footed rat creature. Given his stealthy nature he would run ahead scout out cities and lands for his fellow brethren all the while spreading the accursed plague that he carried with him. He wields two daggers known as Green Tears and Red Tears. (Actually drops: “Akkapan's Tear”, 14/19 1h pierce)
The fourth king and perhaps the greatest next to the founder, Meedo, was a mighty warrior and sorcerer in his own right. Worshipped fanatically during his reign, Meedo was known for rebuilding the ruling palace into a magnificent building unlike any other. He also foiled many assassination attempts against his person and expanded his kingdom to include many new lands. When his soul was ripped from its rest and forced into the creation of Bertoxxulous he took the same as the other first three kings. It was that of a hulking diseased humanoid, strongest of the forms given. He wielded a large glaive as his weapon and led a crazed army of terrors along with the other first three kings. (Actually drops: “Meedo's Glaive of Terror”, 13/20 1hs)
The third king of this ancient civilization, he was known as ruler of a peace and harmony. He forged a great treaty with many neighboring kingdoms that lasted many years. When ripped from his rest he was given the form of a hulking diseased humanoid, like the other first kings. Being extremely powerful he led a crazed army of terrors with the other first kings. He was known to carry a large magical artifact with him. (Actually drops: “Rotting Roaring Lion”, 26/32 2hb, int casters only)
Pzo was a warrior monk trained in the ways of self-enlightenment. He led the great enlightenment across his kingdom. Also known for his fondness of arena fighting, his soul was ripped from its rest and forced into the form a hulking diseased humanoid like the other first three kings. He was also known for his weapon called the Fist of Death. (Actually drops: “Green Fist of Death”, 18/22 1hb, int casters only, and Qezzin's Rotting Roaring Lion)
Known as The Founder, the first king was the greatest of all the kings buried within the crypt. He carved his kingdom out of a wild land and forged it with blood and steel. He was a determined warrior with great leadership abilities rarely ever seen. Bhaly was the creator of the legendary item, the Torch of Lxanvom, which was part of a key for the Crypt of Decay. (Actually drops: “Torch of Lxvanvom”, 25/29 1hb, casters only, apparently part of an unknown quest). 
Throughout worlds, planes, and other dimensions there are many different objects of an immense power. These artifacts are only known of legends and rumors spread throughout the various lands. The Torch of Lxanvom is one of these artifacts.
The founding king, Bhaly Adan, of a once great civilization that was destroyed by the machinations of Bertoxxulous created it. The Torch of Lxanvom was placed in the depths of the burial tomb of kings built by Bhaly for him and his ancestors. It was used in the rite of burial ceremony performed upon the kings before they were buried sealing them away in an everlasting peace.
The whereabouts of the torch have been lost since the fall of that civilization. It is said to look like an open torch with a burning blue flame and is known to possess immense power. The power it possesses is said to envelop the user in a guardian shield of light blue flame that provides its owner with some protection. 
Long ago Raex and Vindor were childhood friends in the Kingdom of Skaxron. As they grew up together they played, fought, and competed with each other constantly. Both young men turned out to be the greatest warriors for generations to come. They became pledged as knights in service to their liege lord, the good King Randall. Two years after they were knighted the War of Ages engulfed their continent as a necromancer in service to dark powers made his bid to rule the world. This war caused them both to be separated as they fought the encroaching forces of the necromancer across the land to save their beloved kingdom. Unfortunately many years passed and their king was slain putting the entire world under the rule of the iron fisted dark emperor.
Both Raex and Vindor survived these lean years as mercenaries and they swore complete and utter vengeance upon the dark emperor that ruled the land. They did not have to wait long for someone was listening. Bertoxxulous, Lord of Decay, had heard their plea and offered to assist them for their permanent indentured servitude to him. He knew they were among the greatest of warriors to live and they would aid him greatly in his rise to power. Blinded by the vengeance they so greatly desired, both of them immediately agreed to the deal. With a mocking laugh and a snap of his fingers, Bertoxxulous banished his servant, the dark emperor, to another realm and he accepted these two great warriors into his service. To this day they still do not know he had conquered their world just to get to them. 
Long ago on the continent of Antonica within the world of Norrath there was a small village known as Yawnwater. The village of Yawnwater was a typical village filled with happy villagers. Surrounding the village was a nice landscape of trees and wildflowers. In the middle of the village was a small shrine of a fountain with a statue in the middle in front of a small altar. The shrine was dedicated to the goddess of love, Erollisi Marr. It was located right off of a small river that flowed down into a great lake. However, there came a time when all did not remain right with the happy little village of Yawnwater. On a dark night when the moon was just a silver sliver in the night sky, terror and destruction came down upon the happy little village of Yawnwater. The dark knight, Carprin Deatharn, was determined to prove to his god, Bertoxxulous the Lord of Decay, that he was an exalted spreader of corruption and decay that was unmatched. He came upon the village and set to destroying it. He immediately killed off any resistance and then gathered up the elderly, women, and children who were too weak to defend themselves around the shrine of Erollisi Marr.
Carprin then set to systematically desecrating the temple by performing a series of dark sacrifices on its altar. After the sacrifice he infected the rest of the survivors with an incurable malady that left them slowly wasting away and dying. When Bertoxxulous saw all that his servant did in his name he was pleased and raised him to new levels of power. Carprin joined his master in his domain soon after. 
Within the Plains of Karana in a time not so long ago the clergy of Karana erected a small temple in honor of their lord. Among those present at the building of this temple was young Toluwon a promising new cleric that had recently been raised up from the rank of acolyte. Young Toluwon was one of the most promising clerics to come into the service of Karana in years. He had shown wisdom beyond his years, mastered the honored rituals of Karana in a short time, and performed the extremely difficult Ritual of Thunder and Lightning for the first time in centuries. However, all this was soon to come to an end for young Toluwon for fate had a different path for him to walk.
Young Toluwon returned to his home soon after helping finish up the final building stages of the temple. He wanted to visit the love of his life in the nearby city of Qeynos. When he arrived at his lover's house, he found a small note asking him to meet her at a private locale. Concerned he made his way there immediately to find something he could not believe. His lover was a secret worshipper of the dark god Bertoxxulous. She was with a group of people in brown robes muttering chants to their Lord of Decay. She offered him a chance to join them that he immediately accepted.
When this decision was made, they immediately sent him out to prove his faith. They sent him against his old brethren in the newly built temple in the Plains of Karana. When he arrived they were surprised to see him back so early. He assured them everything was all right, and told them that he needed to get some rest, but little did they know what he was truly planning. Later in the dead of night he crept around and slit the throats of each individual priest within the temple. Then performing the dark ritual that was given to him by the priests of Bertoxxulous he desecrated the newly erected temple. He was now a full-fledged member of Bertoxxulous' clergy. This is how Bishop Toluwon came to join the legions of corruption. As years passed Toluwon rose through ranks into a powerful priest of Bertoxxulous. For his duty given and the unrelenting devotion to the spread of decay and corruption he possessed he was raised to serve his master in his domain. 
Thousands of years ago in lands long gone there was a prophecy of power. It said, 'One shall be born perched between light and darkness. He will grow and one day he will shroud the world in golden light or encompassing darkness. For he will choose.' Avhi Escron was born shortly after this. She was the child foretold in the prophecy and the forces of light and dark waged war over her. As time passed she began to show signs of extreme magical power unmatched by any ever known to the world. The time for her to choose was fast approaching.
As the time came upon her she was tempted by the forces of dark with images of unseen power, wealth beyond imagining, and endless lands to rule. With these images in her mind she chose the side of darkness and the world in an encompassing darkness. Bertoxxulous was among the powers that she now served.
Decay and corruption became a daily part of Avhi's life as she explored the dark arts of necromancy. Creating new dark rituals, and spells became commonplace as she reached the pinnacle of her power. During this time she declared herself fully in the service of the Lord of Decay. Soon after, she brought down a mighty spell of foul corruption upon the land, laying waste to huge tracts of land. And so she continued until one day she was raised to the side of her lord in his domain. 
The Wemmal Family had ruled their tiny self-sufficient kingdom from a small island in the middle of the endless sea for many years. Not knowing or caring about any of the other continents and lands out there it was a self-contained island of peace. One day that peace changed for chance had brought the sole survivor of a shipwreck to a beach on their land. The survivor was Banord Paffa, a cook from a pirate ship that was wrecked in a tremendous storm the night before. The islanders discovered him on the beach and brought him to the royal family.
The Wemmal's were taken with this seemingly charming pirate from lands unknown. They offered him a position on the cooking staff for he knew many exotic dishes that they had not heard of. However, the Wemmal's would soon learn that their new cook had a dark secret. Banford was a worshipper of Bertoxxulous, the Lord of Decay. He set to slowly poisoning the food he served to the royal family. Soon the whole royal family was sick and dying. It was discovered by a healer that he had been poisoning them, but it was to late for the malady was incurable and then each of the Wemmal's were dead because of Banord. The islanders maddened by grief for their beloved rulers lynched Banford. But the dark deity, Bertoxxulous, was pleased with what Banord had done and gave him a new form in the Plane of Disease where he now serves his lord. 
Down in the depths of some forgotten tomb Tarkon Praez, a necromancer in service to Bertoxxulous, was performing experiments on a tribe of rat men he had enslaved. During this time he bred many various rat men but none of them were what he wanted. He wanted a ravenous, festering, and foul breed that would strike terror and fear into the hearts of the pure. Tarkon decided to pray one day to his dark god for guidance. After many hours of prayers, foul rituals and sacrifices Bertoxxulous enlightened him with a vision of what he must do. He would have to travel to the far reaches and find the necessary components to perform a ritual of the darkest evil. The four components he had to gather were a unicorn heart, tail of a phoenix, tears of a virgin, and the blood of a faerie. After many trials and tribulations he had gathered the necessary components and began the dark ritual. What took form was more than he expected. It was an extremely evil crazed race of rat men that carried a foul plague in their blood and minds. He dubbed them the Bubonians and set them upon the land.
The Bubonians tore the land a part spreading disease, death, and destruction wherever they went. This went on for a time until they were banished from the world by a good and noble order of knights. Bertoxxulous then took the Bubonians into the Crypt of Decay and that is where they have festered ever since waiting to lay waste to the world once again.