The Westraven Witch
The Killing Floor
Xavier, Brain in a Frosty Alchemist’s Jar (X)
2 Rot Grub Swarms®
Pendulum Scythes (6 northernmost rows of the northern chamber, less the alcoves)
Spear Gauntlet (S)
The Rot Grub Swarms attack mindlessly, and because of their low intelligence (and half-damage from ranged and melee attack) have no real fear of the pendulum scythes or spear gauntlet.
Xavier will attempt to engage the enemy from maximum range, keeping them busy with Dominate while they struggle with the traps. If any reach the stairs, he will retreat to the second chamber and use a Telekinetic Thrust on the lever to close the portcullis behind him. Then he will resort to Frosty Blast and Telekinetic Thrust to try to keep them away from the bars. If they breach the chamber, he will use Mind Stab on as many as possible before retreating into the southernmost cell and locking himself in (using Telekinetic Thrust to slam the cell shut behind him). Xavier is well aware of the locations of all the traps and how they work.
Reminder: if this avatar of Xavier is killed, the character dealing the final blow will receive a Boon.
Features of the Area
The Pendulum Scythes (TRAP): The 6 northernmost rows of the checkered chamber are a Pendulum Scythes trap (DMG pg 88), with the blades swinging from east to west. The control panel is hidden (DC 20 Perception) in the eastern alcove.
The Spear Gauntlet (TRAP): There are 5 trapped squares in the area forming a Spear Gauntlet (DMG pg 87). The control panel is hidden (DC 20 Perception) in the western alcove.
The Rug: The rug is fairly nondescript excepting a few blood stains. It is not trapped.
The Pit: The pit is 20 feet deep and has smooth walls. (DC 20 Athletics check to climb out.)
The Stone Altar: The Stone Altar in the southernmost room is strewn with body parts. If the players collect them, they will find it forms a complete body. It can be reassembled into the Dismembered Corpse. The simplest way to do this is with a Make Whole ritual, though there are other, sloppier ways, of course. It is not actually necessary to stitch him back together when burying him, so long as all the parts are present. The brain is missing, as it is the one in Xavier’s current avatar (i.e. in the frosty jar), but is not required. (Though killing him has its rewards, see below).
Southeast Cell: if Xavier is able to retreat into the cell and lock himself in, reaching him for melee will be difficult. The lock will take a DC 19 Thievery check to pick (Standard Action), or it will have to be broken (DC 28 Str to break open outright; AC 5, Fort 10, hp 60).
Xavier’s Brain: Xavier’s brain is floating in 3 doses of Brain Fluid of the Mad Alchemist. The oil can be separated into individual single-dose containers.