I really love this adventure! I'm currently playing through a campaign of it and I wanted to offer my impressions of it for people who're curious.

The Story So Far

It picks up from where the cosmic worldbuilding of Mordenkainen’s Tome of Foes left off: the angel Zariel, disillusioned by an eternity of the higher planes doing nothing to stop the slaughter and devastation caused by the Blood War between demons and devils, abandons her holy position to instead become an Archduke of the Nine Hells for Asmodeus. Now the archduke of Avernus, Zariel is free to wage her crusade against the demons without restraint.

Zariel’s first act as an archdevil was to set about raising an infernal army. Rather than do it one soul at a time, Zariel plots to pull entire cities from the surface of Faerûn down into the River Styx. Her first success is the holy city of Elturel, which was suddenly sucked down into the depths of the Nine Hells, ready to have its souls plundered and converted. The next city on Zariel’s list is Elturel’s neighbour...Baldur’s Gate.

This is where the adventure begins.

The player characters have arrived in Baldur’s Gate just as its gates are shut and martial law is declared. Refugees from Elturel have flooded the city, and death cultists devoted to the Dead Three (Myrkul, Bane, and B’haal) are stalking the streets. The characters have been drafted into the Flaming Fist mercenary company and are put in charge of finding the source of the death cultists...which leads to a trail of conspiracy, betrayal, and deals made with devils.

The characters learn that Zariel has taken Elturel, and are tasked with saving it. They must descend into Avernus to rescue the city, uncover the truth about Zariel, and save Baldur’s Gate from a hellish fate. Doing this, characters will race infernal war machines, make deals with devils, and slaughter demons across a hellscape of brimstone and blood rock.

It’s as over the top and metal as a D&D 5e adventure gets!

Heironious Bosch meets Black Sabbath

The look of Avernus is Hell by way of Mad Max; blasted dry wasteland scoured by black metal death machines that scream across it. Devils and warband warriors hang off the sides, flinging attacks at one another. Another point of inspiration is the luridly complex works of Heironeous Bosch, with some many strange creatures doing unspeakable things to one another, rendered in such a way as to make it feel almost mundane. Ordinary. This is every day in Hell. Adjust to it, or perish.

To complement this, the book includes a whopping ten pages of concept art in the back. The vistas and characters depicted within are a boon to Dungeon Masters who need more art to share as examples. Concept art sections ought to be compulsory to adventures of this scale. They enrich the book a lot.

Mike Schley’s isometric cartography of Baldur’s Gate’s many locations and buildings from Murder In Baldur’s Gate remains wonderful. The solid lines and muted colours perfectly balance Jared Blando’s bombastic maps, with their thin lines and rich reds and yellows.

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I'm a big fan of this book and I'm loving the campaign a lot so far. If you're at all curious about the Nine Hells in D&D or are just looking for something different to put your party through, it's a lot of fun!