The Assembly of Grim

Since Shin contracted scurvy during the last fight, it's time that he went back to visit Dr. Wannabe. Everyone makes their way out of the mountains and back to Crystmas only to find that they're being followed by a mute aarakocra with malicious intent. They take out the avian with ease and finish their travels. It turns out that Crystmas is under attack by an invisible threat- The False Hydra. Their time here is spent recovering and investigating the new threat.

The group arrives at their destination only to realize it's the body of a dead leviathan. After traversing through its mouth, they find a black void that leads into the water. They all down a potion of water-breathing and take the plunge. The first fight is against two triton guards and a sea hag coven. The group makes their way through the guards easily enough but is bombarded by the hags as they do so. Namely, Shirai takes a galvanized harpoon to the leg. Shin and Mex take out a hag each, and Shirai finally catches up in time to burn the hag on top of a magical flame (Shirai is the only one without a way to travel unhindered underwater). With three paths ahead, all leading up out of the water, they opt to explore before facing Zhalsuth.

The group makes their way to Dher Boldar, the underground city of the Dwarves. They gain entrance by explaining their quest to Hell and are backed up by the people of Ixam. While they initially wanted to just pass through, they get caught up in a conflict between the Dwarves and the neighboring Drow. The Drow have shut down communications with the dwarves, and many are concerned they've reverted to their evil ways under the spider queen. This turns out to not be the case as the party investigates and finds that the Drow are actually being controlled by an invasive mind flayer colony.

Shin transforms upon entering the sulfur-soaked plane of Hell. Transformed doesn't even begin to describe what his body undergoes. Shin dies here and Oni comes to life from the ashes. The feelings of bloodlust Kell has been trying to keep down bubbles over as he sees his greatest challenge before him. A fight between Oni and Kell breaks out, but Kell is at a disadvantage from the trial that just took place. He's forced to retreat by flying into the open skies of Avernus. Oni pursues but stops when he senses a scrap of his old self. He spots Shirai in the midst of an open battlefield. The group later comes to understand this as one of the many areas a battle of the blood war rages. But, the politics matter not. Oni is determined to destroy any faint image of the weak one, and Kell is about to truly let loose for the first time since Nahgi. The battle ends with Oni finally laying Shirai to rest. Alquam, the Demon Lord of Night, escapes into The Forest of Death. The duo learns that Salethar can be found at the end of The River Styx.

Zhalsuth, Allak, and Salethar have all been stopped while Oni, Mex Vultar, and Kell live to tell the tale. The face of Grim is left in ruin as not every settlement was equipped to handle the rise in demonic presence that occurred over the campaign. Feron, Koledo, and Dher Boldar have all fallen while Esterwood, Phywell, Ulford, and Crystmas have been weakened (Crystmas, in particular, would have fallen without the efforts of the party, and Koledo only fell due to James' assassination of the jarl).