While there is no widely known single book or series titled the phrase likely refers to specific character codes or fan-favorite tropes within the niche of online webtoons, manhwa, or romance novels that feature digital identification or experiment-based numbering.
: A recurring plot point where the leads enter a fake relationship or marriage to solve a personal crisis (like debt or family pressure), only to develop genuine feelings.
: A common trope involves a modern woman—often a chemist or doctor—who dies and is reborn into a historical or alternate setting. In these stories, the romantic tension often centers on the heroine trying to navigate her new "identity" while falling for a male lead who was originally meant for someone else.
If this refers to a specific work, it is most likely a "reincarnation" or "transmigration" story, where characters are often given numerical designations in futuristic or experimental settings. Common themes in these romantic storylines include: Common Relationship Archetypes