Son-In-Law and Crazy Soldier

Because of his mother's poor health, Yang Xiu was born with deficiencies and had been weak since birth. From the age of fifteen, his grandfather sent him to an island dedicated to training international special forces for five years of training. Five years later, he received the news that his grandfather was critically ill. In order to fulfill his grandfather's wish, he became a son-in-law. However, the Xu family thought that he was still the cowardly and powerless waste five years ago...