A Bad Example of a Perfect Curse

Story:

Read manhwa A Bad Example of a Perfect Curse / 완벽한 저주의 나쁜 예 For eighteen years, people called the “living curse” by a brother’s name. To stand in for the brother buried in the earth, she donned his armor and became a knight of the realm, soon whispered about as the palace’s “mad dog.” After being shuffled from company to company, she is assigned as a ducal bodyguard and finally comes face to face with a real curse. The duke should be a year older than her… so why does time seem not to touch him?