Korovyev (spelled Koroviev in the Penguin Classics edition) is one of Woland's entourage in Mikhail Bulgakov's novel, The Master and Margarita. He presents himself to others as "professor" Woland's "assistant and translator," and is capable of creating any illusion. His appearance is characterized throughout the book by a lengthy build, a jockey's cap, a mustache, and a pince-nez with one cracked lens and the other lens missing. He is alternately depicted wearing a checkered jacket and checkered trousers. We first meet Koroviev at a turnstile to which Berlioz is rushing after having been thoroughly creeped out by his first encounter with Woland. He is not named until much later, when meeting with Nikanor Ivanovich. He is only occasionally referred to as Fagott ("bassoon") by the narrator and by Woland. (In the Penguin Classics edition, there is no o at the end of Fagott.) Koroviev is purported to be an "ex-choirmaster." He is close with the mischievous Behemoth, the oversized-cat-like demon in Woland's party who can alter his appearance at will to seem like a human man. In Chapter 28, "The Last Adventures of Koroviev and Behemoth," the gruesome twosome wreaks havoc around town, sowing confusion at Smolensky marketplace and starting a fire at Griboedov's, a restaurant and meeting house for Russia's literary elite. Source: Wikipedia (en)