How Could the Hero's Teammate Be the Demon King!

In the year 556 of the Jialan calendar, a war between humans and demons broke out. At the beginning of the war, human beings who were forced into desperate situations summoned brave men from other worlds under the instructions of the goddess of light and placed their hope in them. However, the brave man failed. The war between humans and demons has lasted for thousands of years. The war has already reached a stalemate, but no brave man has ever been able to approach the Demon King. Human beings no longer have expectations for brave men from other worlds. Lin Xie, an ordinary college student, traveled to Jialandxi and became the 255th brave man. I thought I could achieve great things, but found that the so-called brave men were just cannon fodder for the Holy See. "Since your academic qualifications are not enough, you can only defeat the devil." "Damn it, thirty years in Hexi..." "Okay, okay, don't bully the young man into being poor, right? Please get in the car." The despised Holy See sent him to the border, but he himself failed to live up to his expectations. "Sorry, Kurogane cannot accept missions alone." "Team up? Sorry, our team is full." The lovely poster girl declined his request, and the adventurers' indifference made him frustrated. Until that person broke into his world forcefully. "I'm here to help you! I'm here to help you defeat the Demon King!" Many years later, when Lin Xie wakes up from the Demon King's City, he will remember the noon when he and the Demon King first met.