The younger son of the Mu family, deeply protective of Xia Chuwei. He skipped class to confront his brother Mu Beichen after learning how Beichen had mistreated Chuwei. He openly admits he does not want Chuwei to be with Beichen and physically blocks Beichen from entering Chuwei's room. He is described as having a deep emotional connection to Chuwei, who once took a dog bite protecting him when they were young.
