Su Chengyun is Su Xiaoxiao's younger brother, a college sophomore. After their parents died and grandmother passed away, the siblings relied on each other. He is caring and trusting; when Su Xiaoxiao lies that she owes gambling debts, he immediately applies for loans to help her, fearing for her safety. He is naive about the apocalypse but devoted to his sister. In the previous life, he died saving her, so Su Xiaoxiao is determined to protect him this time. He has a warm personality and a strong sense of responsibility, often calling to check on her.
