Be My Shield, Be My Love

In this world a person killed in one era can wake up in a body in another. Luna Neuman is a general of Da Yong who falls in battle and comes to in the present, inside an heiress of the same name who has been humiliated by her own household. She gets out of the hospital and deals with the stepmother and the stepsister first, which quiets the rest of the Neumans. She needs a place to stand, so she honours the marriage contract the family had already made and marries Theo Eaton, whom the city calls its biggest wastrel. The marriage looks absurd from outside. Theo's family has never counted him for anything, and his mother died in a way nobody ever answered for. Luna can fight, and she uses it to keep him safe while pushing him to stand on his own. Theo drops the wastrel act and turns out to have ability under it. The two of them work against another Eaton and his mother, look into what happened to Theo's mother, and set about taking back the business.