Crawler in Tipid's party who stabbed himself in the neck while fighting illusions.
Cassio was trapped alongside Tipid and Horatio while The Illusionists worked their spells on them. Unable to tell what was real, he stabbed himself in the neck fighting things that were not there, screaming for them to get off of him. His death left only Tipid and Horatio — and when Tipid's Key turned out to have a single charge, only one of those two would leave.
Cassio never learned that the door could be opened. His death is one of the images that still surfaces in Tipid's hallucinations whenever Tipid steps outside a dungeon environment.
Not described beyond dying by his own blade to the neck.
First of Tipid's companions to die, killed by illusion-induced panic rather than a monster.