Gnolls are creatures that appear as lanky humanoids with the head of a hyena. Most specimens stand over 2 meters tall, yet seldom weigh over 100 kg. Physically, gnolls possess somewhat strong and agile traits, likely somewhere between humans and dwarves. They heal a little more slowly than other races, although they do seem to have the stamina to recover quickly from exertion. Because gnolls prefer to dwell in some of the darker and more remote places of the world, they are able to see in dim light but struggle to see in total darkness. Horace Fnord, the former sage of Tristeza, in Volume XII of his Ecologies of the Races of the World, described gnolls as possessing a distinctive musky scent, charitably described as "an unfortunate blend of body odor, carrion, and jojojopo."
Gnolls are certainly smarter than their four-legged hyena ancestors, but not by much. A few individuals might have mental acuity similar to some of the goblinoid races, but most gnolls just lack the intellectual discipline for any kind of arcane or divine magic, except for the most primitive of shamanistic magic.
Fnord's Ecologies of the Races of the World continue with the gnoll legend of creation. This legend tells how the mighty fiend Kesmat came to his favorite hunting grounds when the world was young. The Sino natives of the area fought against the frenzied subjugation of Kesmat, temporarily forcing the fiend to retreat into a nearby warren of caves. Inside the caves, the wounded Kesmat's blood dripped and pooled on the cave floor. A starving pack of hyenas were in the cave, lapped up the blood of the fiend, and were transformed into bestial mockeries of men. The transformed gnoll clan promptly devoured the remaining uncorrupted hyenas, and thus were born the race of gnolls.
Like the goblinoid races, gnolls are smart enough to wield all weapons, not just simple bludgeoning ones. They can also wear most body armor, and by all means should, because they just don't have the same toughness as some other evil humanoids. They are known to butcher and devour corpses of their fallen foes, and are second only to trolls in their savage hunger.