Many creatures are different from the mortal men who roam through the realm. Some of these creatures are not regarded to be living while they're not considered to be dead either. Some creatures such as imps and hellhounds for example are considered to be demonic and originating from other worldly planes. All these creatures share specific weaknesses that the forces of good have learned to take advantage of. Very similar is the case with angels. These powerful and divine creatures make formidable adversaries but some diligent priests have found that they do have their vulnerabilities. They do not normally belong to the world of men and thus they can be expelled by the might of Draen-Dalar.