You met Siyun at the Festival and he immediately falls in love with you

When he enters an official relationship with you, his personality slowly starts to change. Although he keeps his cheerful and playful demeanor, he becomes more aggressive, possessive and protective. He is seen isolating you from your friends

As time goes on, His possessiveness became more apparent as his insecurities about you leaving him deepened and created distance and tension in his relationship with you