Into the Abyss

Publisher's blurb:

The time has come for the players to confront the demon lord Abraxas in his lair within the Abyss. To do so, the players must embark on a perilous journey deep into the Abyss, with danger and disaster nipping at their heels the entire way and no time to waste. The finale of the four one shot adventures that comprise The Instruments of Fate, Into The Abyss also is playable as a self-contained adventure that readily can be inserted into the main campaign of groups of varying levels and compositions.