Barbanas was a wizard in the mortal world for a period of time, but lived a second life of sorts as a flameskull after his death. He dwelled on the plane of Avernus in the Nine Hells, under the dominion of the night hag Mad Maggie.
By and large, Barnabas was as self-important in undeath as he was magically powerful in life. While he was forgetful he had periodic great insights and recalled profound arcane knowledge from his previous existence.
After his death as a mortal, the wizard Barnabas' skull was stolen from his tomb by one of his rivals. It was then turned into his newer form of a flameskull.
Barnabas' rival later formed an infernal pact with Mad Maggie, a night hag from Avernus, and offered up Barnabas as part of the deal. Barnabas was brought into the Knucklebones Gang, a motley band that included other fiends, kenkus, imps and redcaps.
Barnabas was tormented by the gang's redcaps, but was too humiliated too complain. Around the Year of Twelve Warnings, 1494 DR, Barnabas lost a tooth when one of the fey hurled a metal gear at his jaw, causing him to whistle whenever he spoke.