When meeting Mystic Carrion, he believes, that the party is too poor to seek his services. Mystic Carrion then tasks the party with finding Thrumbo, if he is asked if there is anything the party can do for him.
Thrumbo can be located in Vonayn's Home by the docks east of Philgrave's Mansion. He is hiding in a wardrobe in the beach house X: 56 Y: -120. Interacting with the wardrobe causes Thrumbo to come out. After the player character tells Thrumbo that Mystic Carrion is searching for him, Thrumbo panics and explains that he and his companions were normal beggars until they were killed by Mystic Carrion and unwillingly turned into his undead servants.
The party can either help Thrumbo or kill him and return him to Mystic Carrion.
After speaking with Thrumbo, he asks for the party's help in freeing him and his companions from servitude. Thrumbo speculates that Mystic Carrion is a Mummy Lord, who can only be killed once his heart is destroyed. He suggests that the cellar beneath Philgrave's Mansion is a good place to start.
While investigating, the party will find Mystic Carrion's Ancient Lair in the Undercity Ruins. A book will reveal that Mystic Carrion's heart is hidden in Thrumbo. If the party return to Thrumbo with this information, he ejects the heart from his body, allowing it to be destroyed by the party.
Once Mystic Carrion is killed, Thrumbo and his friends return to the Mansion to thank the party, free at last from the Mummy Lord. Thrumbo will replace Mystic Carrion as a Trader.
