From Ardrana

Gnolls are large, evil, hyena-like humanoids that roam about in loosely organized bands.

While the body of a gnoll is shaped like that of a large human, the details are those of a hyena. They stand erect on two legs and have hands that can manipulate as well as those of any human. They have greenish gray skin, darker near the muzzle, with a short reddish gray to dull yellow mane.

Gnolls have their own language and many also speak the tongues of flinds, trolls, orcs, or hobgoblins.

Note: Gnolls originally appeared in this form in the 2nd Edition Monstrous Manual for the AD&D game from TSR. Their use here is for the purposes of providing context for the campaign only.