This talisman causes its owner to appear and detect as undead to all non-evil non-undead (effectively -8 CHA, or minimum 0 total CHA modifier). Most good-aligned creatures may attack the player, believing them to be undead, supernatural, or evil in some way.
However, it has no such perceptual effect on evil and undead creatures and magic, rendering this talisman useless as a disguise "behind enemy lines".
Discarding the talisman removes the illusion.
Photo by Daniel Jensen. Unsplash License.