Tomb of the Nine Gods

The Tomb of the Nine Gods under the ruined city of Omu in Chult housed the remains of the city's nine trickster gods.

History
After the lich Acererak murdered the nine gods of Omu, he enslaved the city's inhabitants and forced them to build the Tomb, employing a number of them as architects and designers for the tomb's traps. The Omuan who designed the most effective traps was turned undead, and made into the tomb's overseer. After finding an Atropal, Acererak placed it, along with an artifact known as the Soulmonger, on the lowest floor of the dungeon. The dungeon was conquered and the atropin destroyed by a group of adventurers in the 1480s DR.

Inhabitants
A numer of creatures, undead or otherwise, were left behind in the dungeon by Acererak as guards. Some of note are listed here.
 * The nine trickster gods of Omu - Of particular note were the nine trickster spirits that had been worshipped in ancient Omu, before Acererak defeated them. Their spirits were captured in certain magic items, and placed within specially designed chambers within the tomb.
 * I'jin was a fickle and unpredictable chaotic neutral goddess.
 * Kubazan was a wild and spirited chaotic good god.
 * Moa was a truthful and kind lawful good god.
 * Nangna was a selfish and cruel neutral evil goddess.
 * Obo'laka was a nervous and obsessive lawful neutral goddess.
 * Papazotl was a shrewd and conniving lawful evil god.
 * Shagambi was a wise and virtuous neutral good goddess.
 * Unkh was a self- absorbed and indecisive neutral goddess.
 * Wongo was a violent and deranged chaotic evil god.
 * Tomb dwarves - Acererak captured, killed and reanimated a number of native albino dwarves to serve as a labor force to maintain and repair the dungeon as time went on.
 * Tomb guardians - Armored flesh golems were sent to patrol the tomb and trigger traps. They were forged by the tomb dwarves from slain adventurers in a kiln at the second level of the dungeon.
 * Withers - The Omuan formerly known as Gorra designed some of the tomb's most insidious traps. As a reward, he was turned into a wight and given the task of overseeing the tomb and the tomb dwarves. He used a scrying pool to monitor the tomb and a number of crawling claws to perform tasks for him. He retained a sense of curiosity from life, and enjoyed quizzing adventurers that made it all the way to him before killing them.
 * Belchorzh - A beholder lived in a massive chamber at the tomb's third level, using a large number of eye growths to observe and attack invaders. It was rendered permanently invisible by a Wish-spell, and enjoyed taunting invaders as it fought.
 * Blind Artists - a number of blind undead lived on the fourth level of the tomb, where they painted grotesque scenes of carnage and death that occurred in the tomb.
 * Omu Royalty - The queen of Omu, Napaka, hailed as the Sun Queen, attempted to offer herself in her people's stead when Acererak destroyed Omu. Acererak was impressed by her courage. Not enough to spare her people, but enough to give her a gilded tomb within the tomb's 4th level, as well as letting her spirit pass on undisturbed. Her ten-year-old granddaughter, Nepartak, was not as lucky. She was turned into a flame skull, and left on the first level of the dungeon, where centuries of isolation made her block out all awareness of the trauma.
 * G'lyh'rul - Acererak enslaved an Aboleth and left it on the 5th level of the dungeon. The trauma of Acererak's enslavement made it develop a split personality. It's original personality awaits the atropal's ascension to godhood, believing it to herald the end of the gods. It's other personality is far more benevolent. It acts like a humanoid child, curious and gleeful.
 * The Sewn Sisters - A coven of night hags aided Acererak in constructing the soul monger, and now acts as the atropal's nurses. Widow Groat, Baggy Nanna and Peggy Deadbells. Each has a hag doll forged with the soul of a child.
 * Atropal - The atropal is consuming the souls gathered by the soul monger on the final level of the dungeon. Acererak plans for it to become a death god, who will consume all of Toril, and defeat the gods themselves.