Gang-du grew up with no mother and a neglectful working father, so he had to fend for himself to survive during his childhood. During that time, he lacked protein when he needed it most, so the malnutrition turned him slow-witted and into a bit of a heavy sleeper. His siblings look down on him as a failure and a disappointment, while only his father, who tries to make up for the love he had not shown for him, and his daughter, though she's embarrassed by him, show him any respect whatsoever. Gang-du is not a particularly competent father: he feeds his daughter beer and he can't even afford to buy her a new cell phone. Still, he loves her very much, and when she is captured by the monster, he fights with all his might to save her.