Divine Eagle: Auntie, Don't Be Like This

An engineering student in the 21st century traveled back in time to Yang Guo, and the next day was the Xiangyang Martial Arts Conference. He had never experienced anything before, but things after that had to change. How could Xiao Longnu be separated from him for more than ten years when she was in great power, and how could such a prosperous dynasty in the Song Dynasty be destroyed under the iron heel of the Mongols. As a time traveler, how could I not do something at such a critical time point?