Nabassu

The insatiable nabassus prowl the multiverse in search of souls to devour. If they think they can kill a creature and consume its soul, they attack—even if that other creature is a demon, including another nabassu.
Most other demons shun nabassus and force them to live on the fringes of the Abyss. There, nabassus pick off weaker demons or, if the situation warrants, gather in packs to take down larger prey. Some especially powerful nabassus even search for demon lords’ amulets.
Whenever magic pulls demons from the Abyss to the Material Plane, nabassus try to get summoned so that they can embark on a feast of souls there. A summoned nabassu seeks to break free so that it can devour the soul of its summoner and then feed on the souls of whatever other creatures it can catch. One way a summoner can avoid this fate is by providing a steady supply of souls to the nabassu, which might persuade the demon to be cooperative—as long as the supply lasts.

Encontering The Collective

The Collective first encountered a Nabassu when in Myltar's shop. Myltar had been feeding it the souls of the local populace. When Borf ran into the darkness that the nabassu has around it, the nabassu very quickly knocked him unconsious. Luckily Borf gained consiousness and warned The Collective that it was in the shop. Myltar was arrested and Frilla removed the nabassu by returning it back to the nine hells.