Sure, he’s got plenty of guises, but it’s for the shape pictured left that we remember Nyarlathotep. Called the Howler in the Darkness, or God of the Bloody Tongue, he’s got a bit more personality than many of Lovecraft’s creations. How he howls at the moon with a tentacle for a head is anybody’s guess.
Nyarlathotep has had a couple (at least) of model incarnations. RAFM still produces their version, though I like Grenadier’s better. Any of them would be suitable as a daemon prince in your favourite wargame.