In the Chilling Tales adventure “The Taskmaster’s Leash” The nameless Barbazu was a fiend and barbazu who secretly replaced Captain Domini Tisiphanes, the captain of the Chateaufaux militia. Just before the Grand Conjunction collapsed, sending these lands hurtling back to the Demiplane of Dread, one domain, Dementlieu, touched briefly on the lower plane of Baator. When this happened, a number lower-planar denizens were drawn into Ravenloft
Chief among them was a foul amnizu, a horrific little fiend with a bald head, stubby arms and legs, bulging eyes, fang-filled mouth, and black, leathery wings. The other newcomer was a barbazu, a violent and cruel creature with a long tail, clawed hands and feet, pointed ears, and a wire-sharp beard. A number of larvae (mindless, misshapen monsters with worm bodies and humanoid heads) also entered Dementlieu.
The head of Chateaufaux itself, Mayor Henri Melano, was likewise replaced by the amnizu devil. Once in place, the pair set about corrupting the local population. They introduced into Chateaufaux’s water supply a powerful hallucinogen harvested from the glands of a hamatula, a lesser baatezu, (the fiends had this with them when they were drawn into Ravenloft), check the Something in the Water Dread Possibility from the Dementlieu Gazetteer.
The Black Watch was created to this end with the barbazu as its captain. The Black watch was an elite unit of the town's militia constituted through the promotion of the most corrupt of the extant members who were little better than thugs. The Black Watch Militiamen seized, beat, and murdered citizens in the streets on the thinnest of legal pretexts.
Only a handful of people in Chateaufaux -those with extremely powerful wills- could see the true forms of the fiends. Should they had revealed what they had seen, they would face an unpleasant death at the hands of the fiends. And so those who realised that two monsters had taken over Chateaufaux had either gone into hiding or were playing along with the illusion, lest they be imprisoned and killed. The Darklord who rules Dementlieu, knew a portion of his land has passed from his control to the fiends, but has been unable to muster a force capable of ousting the fiends; he didn't want to send in militia forces and alert other citizens in the domain to the difficulties in the city. He hit upon the idea of tricking Rudolph Van Richten to deal with the problem for him.
When Van Richten arrived he had a meeting with the mayor, Henri Melano. Seeing through the illusion and the "Mayors" true form he was upset and started babbling about monsters in the inn where he stayed. A few minutes after his return, a Black Watch patrol came to the inn. They searched Van Richten’s room, then arrested him on a charge of libeling the mayor and imprisoned him.
Fortunately, the reign of madness and terror instituted by the devils did not last long when a group of adventurers, who had been contacted by the legendary monster hunter, liberated Van Richten and fought the fiends. The roles of captain of the militia and mayor were quickly placed back in human hand and both devils were presumed destroyed in the overthrow of their regime. This is not in fact be the case as fiends in Ravenloft have phylacteries just as liches have. The Amnizu, survived the overthrow of its schemes in Chateaufaux. It was, however, captured and imprisoned, whether at the time or subsequently, by the Fraternity of Shadows which is still using it and its phylactery to form an artificial mistway between Richemulot and Souragne. This artificial mistway connects La Maison Soulombre in Port d'Elhour, Souragne, to Chateau d'Is, the former residence of Erik van Rijn prior to his abandonment of Ste. Ronges, located in Richemulot. The Fraternity modified the Mystic Cage spell to produce this mistway called The Cellar Door. Members of the Fraternity refer sarcastically to the captured devil as "Hizzoner". The nameless barbazu possibly travels the domains searching for "Hizzoner".
