The Good Sister is a monster that appears as a beautiful young girl to lure Qin Jin-Nian. She is described as looking in her twenties, with long black hair, delicate sweet features, and a beauty mark on her left cheek. She wears a white T-shirt with a Jigglypuff image, a gray pleated skirt, flesh-colored stockings, and white stilettos. She floats outside the burglar bars of Qin Jin-Nian's 18th-floor apartment, connected to a distant Flesh Mountain by pig-intestine-like tubes. She speaks in a sweet, clingy voice, alternating between anger, grievance, and cheerfulness. When the Flesh Mountain is attacked, she transforms into a terrifying wax-like creature with black-red viscous liquid, screaming "Open the door" and smashing the window. She melts into a form with uneven teeth and continues to attack. After the burglar bars break, she enters, but Qin Jin-Nian kills her with a shadow knife and war hammer. Her bodily fluids turn into swarms of bugs. She is a representative of the dark creatures that emerge during the Blood Moon, working for the Flesh Mountain.
