Nyarlathotep differs from the other beings in a number of ways. Most of them are exiled to stars, like Yog-Sothoth and Hastur, or sleeping and dreaming like Cthulhu; Nyarlathotep, however, is active and frequently walks the Earth in the guise of a human being, usually a tall, slim, joyous man. Most of them have their own cults serving them, while Nyarlathotep seems to serve them and take care of their affairs in their absence.
Most of them use strange alien languages, while Nyarlathotep uses human languages and can be mistaken for a human being. Finally, most of them are all powerful yet purposeless, yet Nyarlathotep seems to be deliberately deceptive and manipulative, and even uses propaganda to achieve his goals. In this regard, he is probably the most human-like among them.
Nyarlathotep enacts the will of the Outer Gods, and is their messenger, heart and soul; he is also a servant of Azathoth, whose wishes he immediately fulfills. Unlike the other Outer Gods, causing madness is more important and enjoyable than death and destruction to Nyarlathotep. In this sense, he strongly resembles the traditional role of the devil.
Nyarlathotep has many forms (some literature refers to these forms as Masks and claims that he has a thousand of them) and is thus known by different avatars.