Exploring Eberron
The first gnolls were fierce and feral creatures, corrupted by the magical energies of the Return of Power and descended from hyenas. They lived in the harsh wastelands of Olmerrec, fighting for resources and banding together in warbands. Over time, they migrated to distant continents, where they are seen as an unwelcome infestation of monstrous creatures.
Gnolls that are bound to the overlords are vicious and wild. Those who have escaped this bondage still have a fiendish spark within, but they contain and control this power. Some learn to wield it as Warlocks. Others known as hwyri train to fight demons and other supernatural threats. Even free gnolls can be aggressive, but they are gifted hunters and fiercely loyal to those they choose as family.