The GORCHR.ITM is a undroppable item equipped by the Chromatic Demon to enhance its invulnerabilities and ensure it can't be damaged or destroyed by accident or on purpose by the player - for essential plot purposes.
The item provides 77 protections against status effects, string references, certain spells, animation and graphic effects and also implements a Regeneration effect.
The item is removed by a dialogue script after the party frees the demon from its magical cage.