Zhao Yu is a young boy, around five or six years old, who is kidnapped and nearly killed by two criminals but is rescued by Wu Yin. He is described as chubby, earning the nickname “little fatty” from his father. He is brave and articulate despite the ordeal, clearly recalling events and speaking coherently with Wu Yin. He is initially frightened but becomes excited and playful after rescue, giggling as Wu Yin carries him on her back to the police station. He is affectionate towards Wu Yin, calling her “Sister” and inviting her to his home. He is resourceful, remembering his parents' phone numbers to call them. He is also observant, noting Wu Yin's supernatural abilities in dispatching the kidnappers and moving sand effortlessly. He is doted on by his family, particularly his mother Tan Jiayi and uncle Tan Ci, and expresses curiosity about Wu Yin's strength, asking her to lift him up again.
