Waterdeep: Descent into Avernus

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Last week saw the release of Baldur’s Gate: Descent into Avernus, the latest hardcover adventure for Dungeons & Dragons. I was elated to work on the release with so many other fantastic people, especially after I was fortunate enough to also write for the 2018 hardcover adventure, Waterdeep: Dragon Heist. While I was thinking about both adventures, it occurred to me that Dragon Heist likely ends with the characters at 5th level and Descent into Avernus splits at a key point when the characters are level 5. It would be pretty easy to bring the Dragon Heist chocolate into the Descent into Avernus peanut butter. How do you do it? Swap the city of Baldur’s Gate for the city of Waterdeep in Descent into Avernus. More on that below…

Spoilers for Waterdeep: Dragon Heist and Baldur’s Gate: Descent into Avernus below! Proceed with caution!

The Structure

The overall structure of Waterdeep: Descent into Avernus looks like this: run Dragon Heist in its entirety with some major elements of Descent into Avernus chapter 1 thrown in. Those major elements to add are Elturel going missing, Thavius Kreeg, Reya Mantlemorn, the infernal puzzle box, the Shield of the Hidden Lord, and all of the “Candlekeep” section. Then run Descent into Avernus chapters 2 through 5 with a little modification (swapping Laerel Silverhand for Ulder Ravengard).

Swap Baldur’s Gate for Waterdeep

The grim and gritty Baldur’s Gate must be swapped for the bright and shining city of Waterdeep… which thematically is a bit of an issue. After the characters find the Vault of Dragons in Dragon Heist, they’ll be going to Avernus. How do you avoid a complete tonal shift? My recommendation is to play up the bloody gang war between the Xanathar Guild and the Zhentarim. When the characters go out, they might see a body or two in the streets as the result of the war, the City Watch failing to keep a battle under control, or toughs roaming through the wealthier areas of Waterdeep, brazenly showing their affiliations and shaking down nobles in places where it previously would have been unthinkable. With Laerel Silverhand gone (more on that below), law and order are falling apart. My second recommendation is to use the Asmodeus-worshipping Cassalanters as your main villain, given their dark natures and infernal storyline.

Laerel is Missing

When the adventure begins, Waterdeep is in a state of panic. Laerel Silverhand was on a diplomatic mission to Elturel to see if you she could calm tensions between the holy city and its neighbor, Baldur’s Gate. No word has been heard from the Open Lord since her retinue entered the city. Recently a boat of refugees from Elturel arrived in Waterdeep, claiming their city had disappeared. These refugees are now stay in the Field Ward, while the Masked Lords argue about how to investigate the claims and what the disappearance of Laerel might mean for Waterdeep.

The Cassalanter Plot

Ammalia and Victoro Cassalanter (from Dragon Heist) have a plan to save their children. Through her servant Thavius Kreeg, High Overseer of Elturel (from Descent into Avernus), the archdevil Zariel promised to help the couple obtain the Stone of Golorr (from Dragon Heist) so that they can seize Dagult Neverember’s stolen gold and use it to pay off a debt Asmodeus (instead of using the souls of their children). In exchange for harboring the High Overseer in secret, Thavius provides the Cassalanters with intelligence regarding the stone and another powerful artifact to counsel them, the Shield of the Hidden Lord.

Zariel’s Plan for Waterdeep

Zariel hopes that by adding more chaos and bloodshed to the battle in the streets over the Stone of Golorr, she can create a situation in which the Cassalanters rise to power after seizing the stone and ending the city’s bloodshed. She then plans to help Ammalia or Victoro use the noble family’s now-heroic reputation to become the city’s new Open Lord. Once one of the Cassalanters leads the city, Zariel can make a deal with them similar to the one she made with Thavius Kreeg and drag Waterdeep into Avernus.

Adding the Descent Elements

The following elements should be added to Dragon Heist to make the story flow into Descent into Avernus.

Thavius Kreeg, the Puzzle Box, and the Shield

Thavius Kreeg is staying in the Cassalanters’ guest house (see chapter 5 of Waterdeep: Dragon Heist). He keeps the Shield of the Hidden Lord and the infernal puzzle box in the master bedroom (area CG8). If found and confronted, Thavius acts as described in chapter 1 of Baldur’s Gate: Descent into Avernus, claiming the Cassalanters captured him and are forcing him to ascertain the properties of the magic shield.

Reya Mantlemorn

Reya Mantlemorn (Descent into Avernus) approaches finds and approaches the characters after they have had at least one in with the Cassalanters or their forces, but before the characters enter the Vault of Dragons or Cassalanter Villa. This meeting likely occurs during chapter 4 of Waterdeep: Dragon Heist. She approaches the characters because she has heard of their deeds helping others in the city.

Reya’s message is the same to the characters, except that instead of hearing rumors Thavius is in Baldur’s Gate and has been seen in the company of Vanthampur guards, she heard rumors Thavius is in Waterdeep and has been seen in the company of Cassalanter guards. She asks the characters to help her explore Cassalanter Villa to find Thavius with her.


After the characters record the Stone of Golorr and the money from the Vault of Dragons, life in Waterdeep has a chance to return to normal. Mirt, becomes the acting Open Lord of Waterdeep, but he must know if Laerel and Eturel can be returned. He asks the characters to visit Candlekeep and talk to his old friend Sylvira Savikas. She may know how to open the mysterious infernal puzzle box Thavius Kreeg kept or have information that could lead the characters to Laerel. If not Mirt, any worldly or sage-like NPC, such as Vajra Safahr, Barnibus Blastwind, or Jarlaxle Baenre, can tell the characters about Sylvira and Candlekeep.

The journey to Candlekeep and the experiences the characters have there can run as written in Baldur’s Gate: Descent into Avernus. From this point on, you’re basically running the rest of Descent into Avernus.


The final change is swapping Ulder Ravengard for Laerel Silverhand in chapter 2 of Baldur’s Gate: Descent into Avernus. This basically a straight up and down swap. All things Ulder are now Laerel and all things Baldur’s Gate are now Waterdeep. Instead of using her stat block in Waterdeep: Dragon Heist, use the mage stat block from the Monster Manual because Laerel’s strength has been sapped by her connection to Baphomet and her time in Avernus. If Laerel manages to escape Avernus, her strength is restored.

Bonus Points: Undermountain

If you want to keep the connection going, when the characters return from Avernus, they are grabbed by Halaster Blackcloak and transported into a level of Undermountain (from Waterdeep: Dungeon of the Mad Mage) appropriate for whatever level their characters may be. Now they must find their way out of the dungeon to get back to Waterdeep… perhaps just in time for an Invasion from the Planet of Tarrasques.

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