What is tomb of levistus?

The Tomb of Levistus is a piece of Dungeons & Dragons lore and is a part of the Forgotten Realms campaign setting. It is located in the frozen wastelands of Stygia, one of the Nine Hells of Baator. According to legend, Levistus was a powerful archdevil who was imprisoned in the tomb by his rival Asmodeus as punishment for a betrayal. The tomb is said to be filled with traps and dangers, but also contains powerful rewards for those who can successfully navigate it. Many adventurers have attempted to loot the tomb over the years, but few have ever returned.