Osyluth

Bone devils – sometimes called osyluths – serve as taskmasters and interrogators of the devils. They act as law-enforcement throughout Hell, leading many devils to fear their presence. Bone devils delight in torturing mortals and devils alike, causing physical and mental suffering wherever they go. Osyluths, along with hamatulas, make up the bulk of the Servants of Mammon, Mammon's personal army.

Physical description
Bone devils appear to be skeletal humanoids a tall, emaciated fiend with dried skin stretched so tight as to outline and emphasize every bone in its body. It has a skull-like head and a bony scorpion-like tail and exudes a stench of decay. An osyluth stands about 2.74m (9ft) tall and weighs roughly 227kg (500lbs). Osyluths often serve as the informers and police of the Nine Hells, monitoring and reporting on the activities of other devils. Some bone devils have wings, although they do not need them for flight.