Korovyov, Behemoth, and Azazello are Woland's retinue in Moscow, along with the witch Hella: a chatterbox in checkered clothes with a cracked pince-nez, a huge black cat that walks on its hind legs, and a redhead with a bared fang who carries out the harshest orders.
Korovyov, who also uses the name Fagot, presents himself as Woland's interpreter and says he is a former choir conductor. He arranges with the president of the residents' association, Nikanor Ivanovich, the rental of Apartment 50 for Woland, and the bundle of rubles he pushes at him, which Nikanor hides in the ventilation duct and which turns into dollars, leading to Nikanor's arrest. He is the one who receives Margarita and explains the rules of the ball.
Behemoth is a cat "as large as a castrated pig, black as soot or as a crow." He tears off the head of the master of ceremonies Bengalsky at the theater, pulls the Master's novel out from under his own body, and sets Apartment 50 on fire with a stove's benzine. Azazello brings Margarita the invitation and the cream, kills Baron Meigel at the ball, and serves the couple the Falernian that takes them out of Moscow.
On the flight in chapter 32, the moon strips away the disguises. Korovyov becomes a gloomy knight who pays for an unfortunate joke about light and darkness, Behemoth reveals himself as "a demon page, the finest court jester who existed in the world," and Azazello flies like "a demon of the waterless desert, a murderous demon."