That “vessel” was to be none other than the body of Ned Shakeshaft, imbued with the magically embalmed heart of the hero of Trianda, stolen from the Hall of the Never Forgotten, the crypt at Karom’s Fall. Gand felt that if he could interrupt the ceremony to restore Krackshaw, at just the right time, Ned would be restored to life, notwithstanding the decayed state of his body.
A battle ensued, and you defeated the Tiger Claws, although Gand escaped. From there, you used the cube to enter the lower catacombs. There, a group of pale-skinned outcasts showed you the way to a path even deeper, where a gate to the Kathdoril Demiplane sat. You defeated a powerful golem, and entered the plane.

Kathdoril blasted you with heat and oppressiveness, and you wandered until finding the temple of Krackshaw. Interrupted a ceremony to restore the deity, you fought a Reth Rathcore, Simick Tull, and a Ravisher, as well as several Kathoril devils. You emerged victorious, foiling the plans to restore Krackshaw.

You have now wandered back towards the gate, hoping it will lead you out of this horrible place.