Lovely Runner - Characters & Cast

His primary motivation throughout every timeline is his profound and unwavering love for Im Sol. Initially, it's a secret, unrequited love. Once he understands the stakes, his motivation becomes the desperate need to protect her from her tragic fate, even if it means his own demise. He repeatedly tells her that he would rather die saving her than live without her. This singular focus on her safety and happiness drives all of his major decisions.

Sun-jae begins as a seemingly perfect but deeply weary top star suffering from depression. Through the time slips, his past self is revealed as a shy, devoted teenager who fell in love with Im Sol at first sight and cherished that love for 15 years. His journey is one of rediscovery and reaffirmation. Across timelines, his core devotion to Sol remains constant. He evolves from a passive admirer to an active protector, willing to sacrifice everything, including his swimming career and his life, to save her. In the final timeline, even without his memories, he is instinctively drawn to her, and upon regaining them, he embraces his love fully, finally achieving a future where he is not just a successful actor but a truly happy man with the woman he loves.

Her motivation is born from gratitude and love. Sun-jae's words saved her from a dark place, and she feels an overwhelming need to repay that debt by saving his life. This evolves from a fan's adoration into a deep, romantic love. Her core drive is to create a future where they can both live happily and safely, leading her to make difficult, self-sacrificial choices to protect him from their intertwined, tragic fate.

Im Sol starts as a bright but heartbroken fan, confined to a wheelchair and finding solace in her idol's music. Her journey through time transforms her from a passive admirer into an active agent of change. She is fiercely determined, often chaotic, and incredibly resilient. Initially, her goal is simple: save Sun-jae. As she learns more about their connected past, her mission becomes twofold: save him and herself. She grapples with the immense weight of her knowledge and the fear of making things worse. Her arc is about reclaiming her own agency, not just as Sun-jae's savior but as the director of her own life, ultimately achieving her dream of becoming a filmmaker while also securing a future with the man she loves.

Initially, his motivation is to date the newly interesting and unpredictable Im Sol. This quickly evolves into a genuine affection and a desire to protect her. In the later timelines, his motivation shifts to a sense of duty and justice. Inspired by Sol and wanting to make a difference, he becomes a detective dedicated to catching the criminal who threatens them, playing a pivotal role in securing their happy ending.

Tae-sung is initially introduced as a typical high school 'bad boy' and Im Sol's former crush. Through Sol's influence in the altered timelines, he undergoes significant character growth. He moves beyond his superficial persona, showing genuine care and concern for Sol. His arc is one of the most transformative in the series; he evolves from a carefree teenager into a responsible and heroic detective. Though he harbors feelings for Sol, he becomes a selfless and crucial ally, repeatedly helping and protecting both Sol and Sun-jae. He is instrumental in resolving the central conflict with the antagonist, ultimately finding his own purpose and reconciling with his father.