I Traveled Through Ancient Times with the Monster Invasion

"Commander! The 99th round of monster invasion has been successfully resisted!" "Humanity is about to enter the stage of strategic counterattack!" "Commander please issue combat orders!" That day, the disaster prevention commander Lu Zhenqi, who was responsible for resisting the monster invasion, thought he could end the disaster with his own hands. But that was just a trap set by the mastermind behind this disaster. When he woke up again, Lu Zhenqi had traveled to an ancient border city called Xiongtian Pass. There are no advanced weapons or highly developed technology here. There are only three passes made of bricks and stones and guarding soldiers holding cold weapons. What makes Lu Zhenqi even more unbelievable is that the monster invasion has made a comeback from the first round. What should we do? What method should be used to repel these monsters? The people here are about to face a terrible disaster they have never seen before. A wave of monsters like bloody waves has been raging towards Guanqiang. And all Lu Zhenqi can do is to stick to the end with these gatekeepers and defend Xiongtian Pass to the death!