As with other Monster Manual supplements, MM4 contains a variety of new creatures as well as expanded variants on staple D&D monsters such as orcs, demons, yuan-ti, and gnolls. What separates it from past volumes is the level of detail given to each creature subtype, including probable behavior in combat and even a complete pre-prepared encounter complete with a map.
Like other Monster Manual supplements, MM4 presents a variety of new creatures alongside more detailed versions of staple D&D monsters such as orcs, demons, yuan-ti, and gnolls. What differentiates it from earlier volumes is the depth of information offered about each creature subtype, including probable behavior in combat and an entire prepared encounter.