Ubbalux

Ubbalux was an imprisoned barlgura in Avernus, first layer of the Nine Hells, in the late 15 century DR.

History
Once, archdevil Bel defeated Ubbalux and imprisoned him inside a circle of obelisks, telling him that the secret of escaping was inside the runes inscribed into the obelisks. From then on, Ubbalux studied the runes but with no fortune.

In the, Ubbalux was posing as a human wizard, one whom he had previously devoured, hoping to manipulate the next visitors the circle in order to gain their help.