Myrkul

Myrkul, also known as the Lord of Bones, was one of the Dead Three and the second god of the dead, having received it from Jergal. He along with Bane conspired to steal the Tablets of Fate from Lord Ao, which set into motion the Time of Troubles. During that time period, Myrkul was ultimated slain by Mystra in Waterdeep. His his portfolios were claimed by Cyric and eventually went into the hands of the current god of the dead, Kelemvor. Myrkul now drifts in the Astral Plane.

Mask of the Betrayer
Myrkul is largely responsible for the events in Mask of the Betrayer. One of his Chosen was Akachi, a powerful and influential high priest from Mulsantir. Akachi's lover was a faithless wizard who died in an accident, and Myrkul refused Akachi's request to exempt her from being cast into the Wall of the Faithless. Myrkul had constructed the Wall to dispose of unclaimed, faithless souls.

Angered by his god's refusal to spare her the torment of the Wall, he rebelled and launched a crusade into the Fugue Plane to tear down the Wall and retrieve the Founder's soul. Myrkul soon stopped the crusade, though not before the Founder was freed, and judged his high priest as False. As a punishment, Myrkul had Akachi put into the wall where the Founder's soul was placed, but tore him out just before he was fully consumed by the wall, reducing him to a being of hunger and emptiness. This entity was the Spirit Eater curse.

Myrkul's ulterior plan was to let the Spirit Eater loose in the wilds of Rashemen, a land rich in spirits. The spirit eater would take control of another mortal as a "mask," slowly devouring that person's identity and soul (transferring it to his spot on the Wall), and then moves on to the next. This being became a fearful creature of Rashemi folklore, ensuring Myrkul would not be forgotten and his consciousness lives, even after his death in the Time of Troubles.

Akachi's younger brother, Eveshi, also known as Araman, was another involved in the Crusade. Myrkul gave Araman a choice: Suffer the same fate as Akachi, or bring the Founder back to the Wall. Araman chose the latter, believing he finally once made a choice for himself and wanted to correct his brother's mess, and was made ageless by Myrkul with his soul bound in the Fugue Plane.

The Founder, in search of a way to end Akachi's suffering, eventually went to Myrkul's god-isle in the Astral Plane, and tortured him to gain information on ending the curse. Myrkul stated that if the one cursed by the spirit eater where to retrieve his/her soul from the Wall, this would end Akachi's hunger. Though the Founder believed him, this was a lie; only the accursed would be restored. Restoring Akachi required gathering fragments of his identity, something Myrkul incorrectly believed was destroyed.

Eventually, the PC, having been dragged into Rashemen after the defeat of the King of Shadows, was afflicted by the curse and soon retraced the Founder's footsteps to Myrkul. Myrkul, still cruel and manipulative even as a dead god, mocked the plight of the player and his/her companions. He revealed that the curse was Akachi's punishment, and the PC is just the latest host. He revealed that an "ally and enemy" was waiting for him/her beyond a second portal, with the Silver Sword of Gith. This portal led to the Founder's Sanctum, where she revealed everything.

At the end of the meeting, the player has the option of turning the Spirit Eater curse against Myrkul. The player can use Devour Spirit (or giving One of Many, if present, the honors) to devour the dead god. This only absorbs him, and his presence is still felt while the curse is in effect. The player can also administer poetic justice with Eternal Rest, which gives Myrkul a more permanent retirement. If the player does this, Myrkul's final thoughts are of the irony of being undone by the monster he unleashed upon the Realms.

Trivia

 * Myrkul was voiced by S. Scott Bullock.
 * It is heavily implied that Myrkul was responsible for the "accidental" spell backfire that originally killed the Founder, as a test of Akachi's loyalty.