Derpy is a friendly, if somewhat dim-witted, feline. His behavior is similar to a common housecat, and he is shown to enjoy being petted by others. However, unlike most cats, he tends to be obsessed with righting knocked-over objects, as shown during his first encounter with Rumi when he accidentally knocks over a potted plant on her patio and repeatedly tries to set it upright again with his paw. Despite his eccentricities and lack of intelligence, he is shown nevertheless to be very loyal and affectionate to the people he cares about, as shown when he tries to convince his owner Jinu not to go through with Gwi-Ma's plan to steal the souls of the citizens of Seoul by offering Rumi's bracelet to snap him out of it. Sussie, in comparison to their feline companion, is more sassy and competent in terms of intelligence and common sense. Frequently sporting an exasperated look on their face, Sussie tends to be sarcastic towards Derpy, who constantly annoys them with his tendency to get distracted by fixing fallen objects. They also tend to be something of a kleptomaniac, with their owner Jinu claiming he originally made Sussie's hat for Derpy before Sussie stole it from him. Despite their mischievous behavior, they nevertheless care about Derpy and his owner, and at the end of the day, they are one of Jinu's most loyal companions.The characters' names were not revealed in the movie; however, director Maggie Kang later confirmed that the tiger and magpie are officially named Derpy and Sussie, respectively. Derpy is confirmed to be a male. Sussie's gender is currently unknown. Derpy and Sussie's "Tiger and Magpie dynamic" is based on "KKachi Horangi", a form of Korean "Minhwa" (folk art) that depicts tigers and magpies. Another word for the minhwa is "Hojakdo", in which "Ho" means "tiger" and "Jak" means "magpie". When Derpy moves, a creaking bamboo noise can be heard. It was confirmed in an interview that while Derpy and Sussie "live between these two worlds", they are not demons, and it is left a mystery as to what they are. They are the only supernatural creatures in the movie that aren't demons. Derpy and Sussie are two supernatural creatures Derpy is a large, supernatural feline that resembles a tiger. He has cerulean blue fur with black and white stripes across the upper part of his body, and rosette patterns along his chest. His eyes are red with a yellow cornea and often look unfocused, which gives him a permanent derpy expression. He notably sports a perpetual grin on his face that shows off his sharp white teeth. He also has a set of tusk-like teeth that poke out from the top corners of his mouth. Sussie is a six-eyed supernatural magpie with a set of three eyes on each side of their face. They have black and white plumage, with the black feathers being mostly on the top half on their body and their tail, and the white feathers being mostly around their mid-section. Their most distinct feature is the small black Korean Gat Hat on their head, which was originally given to Derpy before Sussie stole it for themselves.