Brennan returns to Exandria's age of Calamity to DM the series Downfall. Six player characters, beings of god-like power, seek to avoid their own destruction.

From criticalrole.fandom.com - "Critical Role: Downfall is a three-part special set over a century into The Calamity, following six divine figures and 'the role that they played in the destruction of the flying city of Aeor'. This special is part of the third campaign of Critical Role and will run from 'Downfall: Part One' to 'Downfall: Part Three' in July 2024... Downfall will be a standalone special which requires no prior knowledge of either Critical Role or Exandria Unlimited. Brennan Lee Mulligan described it as a prequel within the narrative of the third campaign. While the special is intended to have 'its own impact', it is also 'specifically' aimed at having an 'impact for Bells Hells and for Campaign three'."

The Cast of Downfall:
Laura Bailey – Nahal / Emhira
Taliesin Jaffe – Ash / Asha
Ashley Johnson – Luz / Trist
Noshir Dalal – Edam / The Emissary
Nick Marini – Aru / Ayden
Abubakar Salim – Coru / SILAHA
and
Brennan Lee Mulligan as the Dungeon Master