Built skeleton army evil merit badge

A skeleton army comes with significant advantages over its living counterpart: no need for food, water, or shelter. Atmosphere means nothing to them; they are resistant to cold (magical and mundane), projectiles and bladed weapons. Physical strength and duration of animation depends on the competency of the raising necromancer.

Pro-tip: Undead armies are occasionally criticized for having no personality. Consult with your necromancer before work begins to rectify this.