Hwangjewa Bimil Yeonae Junginde Naneun Geugeol Molla

Story

My Perfect Boyfriend Was Actually a Tyrannical Emperor? In a romance novel where a war-obsessed tyrant falls in love with a sun-like saintly heroine, Carolina is reincarnated as an extra with absolutely no connection to the original plot. For Lina, an ordinary working girl who cares more about whether she has to work late tomorrow than about the romance of the century, her mundane daily life is turned upside down when, one day, a boyfriend with dazzling good looks appears as if by fate... ...I had no idea back then. “...Lina.

Synopsis via AniList (English).