Mister Munshun (a.k.a. Lord Malshun, the Monday Man) is a demon and high-ranking courtier of the Crimson King. He, along with his willing human host Charles Burnside, is the principal villain of the Stephen King/Peter Straub collaboration Black House, the sequel to their earlier collaboration, The Talisman.
In Black House, Munshun is tasked by the Crimson King with acquiring child-slaves and searching for new Breakers. Munshun uses geriatric serial killer Charles Burnside ("Burn-Burn") as his human agent. Burnside carries out the abductions, and in return Munshun provides him with a steady supply of victims.
Munshun is gleefully sadistic, and has possessed several cannibalistic serial killers throughout history, most notably Albert Fish. Mister Munshun's human hosts accept the possession willingly. He does not force or coerce them to kill or to eat their victims, he merely assists them in their "work."
Munshun dwells in a hellish, volcanic region of End-World known as the Furnace Lands, where he oversees the Big Combination, a skyscraper-sized power plant with enormous turbines rotated by hundreds of stolen children from many worlds "on burning, bleeding footsies." The children are driven on by lizard-like creatures wielding whips. Near the Combination, Munshun has built a small shack for his human accomplices, where they can torture and kill their victims uninterrupted.
Munshun cannot exist physically in our world, except within the walls of Black House, which Charles Burnside built with Munshun's guidance.
Munshun's minion is a being called Gorg (a word that means "death" in the Language of the Dead), who appears in our world as a large, talking crow. Little is known about who or what Gorg is, but the creature has the ability to beguile and hypnotize, and Munshun uses him primarily as a tool to pacify children, making them easier to abduct. When the wrong man is arrested for the Fisherman murders, Gorg convinces the mother of one of the victims to lead a lynch mob intent on killing the man.
Gorg was shot (and apparently killed) outside Black House by Jack Sawyer.
"Munshun" and "Malshun" are phonetic approximations of the demon's real name, which is said to be unpronounceable by human speech.
Albert Fish called him "the Monday Man."
Munshun is described as tall and bone-white, with black, claw-like nails, a hideously enlarged and elongated head, red lips, shark-like teeth, and a single, enormous, black eye. When looked at directly, however, his appearance constantly flickers and changes: sometimes he seems to have two eyes, or a tuft of bright orange hair sprouting from the top of his normally bald head; sometimes his head seems only slightly enlarged, while other times it appears to be larger than his body. He wears a black three-piece suit and a red tie. The waistcoat is buttoned with small bones.
His voice has a disturbing, inhuman quality, and he speaks with a bizarre accent described as sounding "like a Frenchman trying to imitate someone speaking English with a German accent." He often playfully repeats the last syllables of words and occasionally curses in German.
Munshun/Malshun was killed by Jack Sawyer, who smashed the demon's head open with a baseball bat infused with residual energy from the Talisman.