Kill That Dark Moonlight

[Two male leads + interstellar setting + military academy life + faux uncle-and-sister-in-law relationship + spirit forms] In the year 2312 of the Galactic Calendar, pirates attacked Proxima Centauri, killing the finance minister and his wife and leaving behind their thirteen-year-old child. Because of a marriage pact, the child was taken in by the Ji family. On that very day, something called the System came to Ji Xinyi. It told Ji Xinyi that he was living inside a book, where he was a cannon-fodder villain. The child who was about to arrive, his older brother's fiancé, was the beautiful, strong, and tragic male lead's beloved. Ji Xinyi would bully him until he became a dark-hearted rival, then the boy would join forces with all the people who came to their senses and fell for him to destroy Ji Xinyi. After hearing this, Ji Xinyi gave a disdainful laugh. Who cared? If he'd decided to be a villain, he might as well see it through.