Spirits of the dead, trapped in a half-life between the Material and Ethereal Planes. All are incorporeal, and can only be harmed by other incorporeal creatures, magic weapons, creatures that strike as magic weapons, spells, spell-like abilities, and supernatural abilities. They are completely immune to any non-magical attack forms and take half damage from corporeal sources except for force effects. They can move through objects and ignore armor.
First Reference: Chapter 50 (Part 1)
Other Notable References: —