A Loser in the History Department? I, Liu Feng, Will Save Guan Yu First!

A history graduate student died suddenly after staying up late, and then opened his eyes and became Liu Feng of the Three Kingdoms. It happened that Guan Yu was defeated in Maicheng. Historically, he was sentenced to death by Liu Bei for refusing aid. "We must save this time!" He ordered his troops to rush to rescue at starry night. In the flames of war, he beheaded Pan Zhang and retreated from Lu Meng. His blood-stained shirt stood in front of Guan Yu. "Uncle Yunchang, my nephew is late!" Guan Yu narrowed his eyes and raised his sword: "You are not my nephew, who are you?" ——He forgot that he was still facing Liu Feng. (My brain is gone)