History
Baelroth is (presumably) an entity invoked as part of spell, including "Begone, Blight! Begone, Pestilence! In the names of Galigothiel and Baelroth, I abjure thee begone!", an spell intended to drive goblins from village grain stores.
The spell was used by Doctor Strange to exorcise demonic entities tied to the Undying Ones,[1] then, merging with Aradnea (who had been bred and mystically engineered to serve as a conduit for the Undying Ones), to banish all the Undying Ones possessing Atlanteans during the Fear.[2]