영웅은 죽고 싶다 (Associated Names)

Nineteen-year-old Kim Geonho was physically enhanced and time-warped into the 23rd century. For fifty painful years, he devoted himself to stop the apocalypse in the future before returning to the present as his nineteen-year-old self. The dangerous future was prevented, and no one knew of the suffering he endured. No one knew about the hero…