Sisyphus — Characters & Cast

Initially driven to uncover the truth about his brother Han Tae-san's disappearance, which later evolves into breaking the temporal loop to save Kang Seo-hae and avert global nuclear war.

Begins as an arrogant, pill-dependent, self-absorbed tech billionaire consumed by chronic survivor's guilt over his brother. Through his alliance with Seo-hae, he evolves into a deeply empathetic, brave protector willing to sacrifice his legacy, his scientific crowning achievement, and his own life to rescue humanity and the woman he loves.

To fulfill the survival instructions left in her future diary by protecting Han Tae-sul and preventing the catastrophic launch of nuclear missiles.

Forged in the brutal ruins of a post-nuclear wasteland, she arrives in the past as a relentless, emotionally guarded survivalist. Interacting with 21st-century civilization and Tae-sul rekindles her warmth, vulnerability, and humanity, shifting her from a soldier obeying a survival diary to an autonomous woman choosing love over pure combat instinct.

To punish human society for past indignities and force Tae-sul to validate his nihilistic worldview that humanity is inherently evil.

An alienated, abused classmate from Tae-sul's youth who developed a pathological hatred for human hypocrisy. After surviving the initial nuclear strike in a bunker, he exploits Tae-sul's future inventions to construct an elaborate temporal trap that ensures the past perpetually burns.

Securing downloader access to locate and protect his estranged wife and daughter.

The operator of Asia Mart, an illegal temporal trafficking hub. While appearing cold, calculating, and predatory toward newly arrived travelers, he is ultimately driven by desperate, agonizing remorse regarding the family he abandoned in his original timeline.

To escape crushing poverty and protect Seo-hae, with whom he falls unrequitedly in love.

A struggling Chinese restaurant worker who accidentally crosses paths with Seo-hae upon her arrival. Winning the lottery thanks to her temporal knowledge, he transforms from a hopeless youth into Seo-hae's fiercely devoted ally, risking his life repeatedly to aid her cause.