By the time they enrolled in Ying De University, Xi Men and his friends had became the F4, an abbreviation of "Flower 4". The F4 controlled the school and were allowed to do as they pleased. Additionally, they issued out red slips to those who opposed them, which caused said person to be bullied until they dropped out.
Xi Men: "Have we met before?"
Xiao You: "No, it's our first meeting."
Xi Men: "I wouldn't forget such an adorable girl."
The F4 became acquainted with Dong Shan Cai, when she incensed Si by protecting her friend. Xi Men was later amused by Shan Cai "declaring war" on them and made a bet on how long she would last. Several days later, he and Mei Zuo ate lunch with Shan Cai and spoke to her about Jing and Lei's relationship. Jing arrived from France a day later.
Si convinced everyone to go on a cruise around Taiwan, instead of the school trip to Hawaii. Xi Men was irritated by the cruise since Si had promised them a "better place" than Hawaii. That night, Xi Men danced with Shan Cai at a party hosted by the F4. Everyone ate sashimi made by Si on the last night of the cruise. At Jing's birthday party, Xi Men flirted with Shan Cai's friend, Xiao You, but agreed to stay away from her at Shan Cai's urging. Xi Men later said goodbye Jing and Lei at the airport. Jing was returning to France, while Lei was going after her.
After photos of Si and Shan Cai were posted, Xi Men and everyone else thought they were dating. Xi Men and Mei Zuo teased Si and asked him about his night with her. The two later attempted to comfort Si, who believed Shan Cai had cheated on him. The incident was cleared up and Xi Men went back to teasing the couple as usual. Following Lei's return from France, the F4 and Shan Cai went on vacation to Okinawa. Si suddenly went back to Taiwan. He later told Xi Men and Mei Zuo about Lei and Shan Cai kissing.
Xi Men: "I envy him. I, for one, can never love a woman so much."
Mei Zuo: "You can, but you're running away from it."
Si forced Lei out of the F4 and replaced him with Chen Qing He. Xi Men and Mei Zuo both refused to acknowledge Qing He as a member of the F4. Si then attempted to expel Lei and Shan Cai, but Dao Ming Zhuang proposed a solution. They split into two teams of three with Xi Men and Mei Zuo on Si's side against Lei, Shan Cai, and Qing He. Si's team almost wins, however, Si quit at the last second. After the match, Si decided to leave for New York. The F4 said goodbye to him at the airport.
Once Si returned to Taiwan, the F4 went to greet him at his home. They spent most of the night waiting, before realizing that Si had gone to see "someone important" to him, aka Shan Cai. The following day, Xi Men teased Si about spending the night at Shan Cai's house. Xi Men and Mei Zuo later urge Si to apologize Shan Cai, after he offended her several times.
Personality and traits
Despite being considered a playboy, Xi Men was respectful and courteous toward women. Nevertheless, Xi Men dated many different women and never kept a steady girlfriend. His relations with women sometimes caused trouble, including angry boyfriends. Xi Men was able to handle them though, being skilled in fighting. Despite being good at basketball, he disliked physical exercise, which he called "boring" and a "waste of energy."