The Castle: Gwianui Sinbu

In modern-day Korea, the Imperial Family holds a secret duty of exorcizing "Imae,'' creatures that lurk within paintings to feed on the grief of humans. But such beings can only be detected by people like Jo Yu-Yeon who possess the Sacred Eye. Despite knowing that Crown Prince Geon needs her special vision, Yu-Yeon gets caught up in a deceptive marriage plan to make it seem like another woman has her ability instead. But no secret can be kept forever. What will become of Yu-Yeon once it's revealed that she is the keeper Geon has always been looking for? (Source: Tappytoon) Note: Includes seven extra chapters.