Li Wanbai's best friend since elementary school, who has now become hostile toward her. According to Ye Xiruo, Su Chengzi stole Li Wanbai's design drafts to steal the spotlight and deliberately sabotaged Li Wanbai's date with her crush, pushing her toward Yu Baichuan instead. Li Wanbai finds Su Chengzi's number unreachable and is blocked on WeChat and text messages. Su Chengzi speaks to Li Wanbai with disgust and refuses to believe her amnesia claim.
