Solidified Spirit Body

[b-dog]

I was thinking of demons and other solidified spirit type beings where they are made of a sort of spiritual material that has been solidified. The solidified spirit can be locked out of a room by a door or pushed off a cliff or knocked to the ground or restrained by a rope and so on but the solidified spirit takes no damage from mundane matter thus sword attacks and other weapon attacks hit and even pierce the solidified spirit body but once pulled out the solidified spirit body will reform and will suffer no damage. The only way to harm a solidified spirit is with a Ghost Weapon or using Affect Spirit magic. I think this would fit the AD&D concept of demons and devils where only magical weapons can affect them. Also Wraiths could be like this too but they would be more spectral and mundane weapons go through them like some sort of ghost but wraiths could be locked out of rooms by doors or restrained but they would likely have some power to become insubstantial.