You have served an evil deity for years. Doing so has allowed you to achieve abilities that make you seem god-like amongst the common folk. Attaining the level of power you now hold has not been easy. You have sacrificed much: lives, morals, contentment, and more. It has all been worth it. The time has come for you to leave this world and take your place among the pantheon of Faerûn. No longer will you be a god among men. Now, you will be a god among gods.
Most campaigns never reach level 20. Descent to Ascension is a one-shot adventure designed to give you a chance to try 20th-level play. It is not designed to be played as part of an ongoing campaign. The adventure takes place toward the end of the Sundering and is designed for a party of five 20th-level evil adventurers.