Shadow-poisoning occurs when a shadowbeast of any sort possesses a higher mental or magical aptitude than the victim's natural defenses can overcome. When inflicted with shadow-poison, the entry area will begin to develop a rash-like quality which itches terribly. After a while, the poisoning will spread to the brain and cause severe hallucinations. In the most extreme cases, the hallucinations are so debilitating that the victim will cease to move and suffer silently. Ultimately, all cases of shadow-poisoning are lethal unless cured.
Curing shadow-poisoning is not impossible, but excepting lesser cases, requires the ability of another afterlife being. Millie, who possesses a mastery of light (shadows' natural bane), is able to cure even advanced shadow-poisoning almost effortlessly. In some cases, meditation can cure shadow-poisoning and drive it away. The latter cure is, however, reserved for inferior cases.