Sinillyuui Sarang

A young woman is constantly overshadowed by her genetically enhanced older twin brother, who was created as part of a human survival initiative. Determined to measure up, she meets another enhanced individual named Iron, and they develop feelings for each other. However, their relationship faces challenges, including an accident that forces her to live as her brother. A larger scheme is also at play, aiming to produce a supreme being to control all enhanced humans, with Iron as a potential candidate. Unbeknownst to them, Iron is gradually transforming into a violent, beast-like entity.