The horned head of the nabasu has a cruel and vaguely humanoid face that appears trapped in a constant state of rage and pain. Its ever-pervasive, glowing golden stare is known to strike its foes dead at its mere gaze. Their bodies are tall and wire thin, with gray reptilian skin and large leathery wings and spindly arms that end in hooked razor-sharp talons.

The majority of nabasu encountered outside of the Abyss are nabasu demonlings. These proud creations of the demon lords are sent to the Material Plane to feast on the souls of the innocent until they reach maturity and can re-enter the Abyss on their own. Once there, they devour the physical hearts and mortal souls of their prey, growing stronger and deadlier with each third victim they destroy. Nabasu derive great pleasure from torturing and killing other creatures.