Yao guai are the mutated descendants of the black bear. These vicious creatures are found across the Wasteland, and more commonly the Zion valley. They were named by the descendants of Chinese internment prisoners after the Great War.

Yao guai are large, ursine animals that are descended from the bears that lived across the country before the war. Due to their zombie-like appearance, yao guai may be the bear equivalent of a ghoul, however unlike human ghouls they are not sterile, as evidenced by the presence of cubs.

one of the more vicious creatures of the wasteland, sporting razor sharp claws and teeth and a nasty temperament. Despite this, yao guai exhibit a gentle, familial bond toward one another when found together and can even be domesticated. Yao guai will attack nearly any other animals or people they encounter, including deathclaws. The mutation has greatly extended their lifespan, although practical immortality has only been achieved by ghoulified yao guai, limited to remote populations deep in the irradiated Forrest.  Some of these yao guai are bears that have been born before the Great War.