Levistus is not an imprisoned archdevil, but rather one of the great rakshasa rajahs defeated at the end of the Age of Demons. The war between dragons and fiends raged over the entire surface of Eberron, and Levistus (as he is now known) was imprisoned beneath the surface of the Frostfell. Levistus is served by a particularly active sect of the Lords of Dust. Legend tells that this powerful fiend actually did once slip his bonds, briefly wreaking havoc on the Frostfell before being imprisoned again. That brief taste of freedom makes him loathe his imprisonment all the more, and encourages his followers—if Levistus was freed once, he can be again. It was during this brief period of freedom that the rajah acquired his modern name. His original name is lost to history—or a closely guarded secret.
The iceberg city of Icerazer, described in Chapter 7 of Frostburn, is governed by followers of Levistus. Its population includes a number of rakshasas rather than devils, but the city is otherwise as described in the book. Azediel, the half-fiend Matriarch of Icerazer, seeks tirelessly to find the Crown of the Black Fire, a mighty artifact dating from the great war between the dragons and the fiends.