Cauldron of Sapphire, the penultimate Tier 4 adventure of Season 7, is a superb adventure. Robert Adducci crafted what I believe is the first regular-series DDAL adventure to get Tier 4 right – and yes, I do include my own efforts in that. (I don’t include the special Epics or Author-Only adventures, as I haven’t run those yet!)

Cauldron, like my Eye of Xxiphu, mostly takes place underwater, but raises the challenge by putting the characters near a volcano. This means that they must also deal with superheated, acidic water! The visuals of the adventure are excellent. I delighted in an early scene where great masses of pumice rose up from below as the party descended.

Most of the encounters don’t immediately begin with an attack and provide opportunities for role-playing. My players delighted in that and caused much chaos amongst their foes. Not every monster has the same motivation, and the characters can save some from corruption. The adventure isn’t “everyone lives!”, but it does offer a lot for players of all types.

The imagery gets more disturbing as the adventurers get closer to the conclusion; there are serious forces of corruption loose. The great ur-demon Dagon can potentially make an appearance as the climax. The choice of monsters reinforces the theme of corruption, and it’s great to see the use of a sibriex from Mordenkainen’s Tome of Foes. My group found the combat encounters – those the party didn’t talk their way past – challenging. It was also nice to have an adventure where the conclusion wasn’t the players facing Red Wizards and casting multiple meteor swarms!

As with many D&D Adventurers League adventures, the structure is mostly linear. Unusually, there are no maps at all. It’s well-written for the most part, but somehow omits the nalfeshnee stat block, a monster that appears in a couple of encounters. The WotC mandate of not modifying the printed stat block in the adventure but instead noting changes in a sidebar was frustrating, once again. Robert used reskinned monsters well.

There are a lot of environmental hazards present in the adventure, and the number of moving parts can make running combats tricky. However, the results were well worth it.

Cauldron of Sapphire is a superb adventure and, even if you don’t play in the D&D Adventurers League campaign, it’s worth examining its techniques. Strongly recommended!