Sinipsawoneun Mawang

A powerful demon lord awakens in modern-day Korea after centuries of slumber, seeking vengeance against the hero who once defeated her. She discovers that the hero is now long gone, leaving only his descendant, a struggling office worker named Yong-Rae Kim, who leads a joyless and unfulfilling life. Believing that ending his life would be an act of mercy, the demon lord instead chooses to improve it. However, Yong-Rae's unfaithful girlfriend and the oppressive demands of his workplace complicate her plans. The demon lord aims to dismantle the rigid office structure and awaken the dormant hero traits within Yong-Rae to make her revenge more meaningful.