The War Lord And His Fake Bride (Official) summary:

Read manga The War Lord and His Fake Bride (Official)"I've come to get my wife." On the day of the wedding, the groom, Koumei Oh, showed up soaked in blood. The bride, Meirin, couldn't hide her horror at the sight. The Oh family, a military family, has been cursed to die by the age of 30 due to their violent acts in battle. In this age, doctors have lost their position in society and the Xian have been entrusted to save people. The emperor, hearing rumors that "those who make a vow with a Xian and produce descendants shall never perish," arranged for Koumei to marry Meirin, a Xian. However, Meirin doesn't actually possess the powers of the Xian and is marrying Koumei in place of her older sister, Shenrin. Meirin fears she may be killed if this lie is discovered, but Koumei turns out to be different from the rumors, and Meirin begins to fall in love Published by Comicle Original.