I Will Eventually Become a Night Watchman

In this world, there are people, elves, dead disciples, demons, giants... Jiang Yan, a college student, was still struggling for tomorrow's exam in the middle of the night, but suddenly he entered an alien space between the worlds and became a stranger. But he looked at the fifty-meter-tall giant in front of him, and then looked at his small body... Damn it, I'm not Eren Yeager. Isn't it too difficult for the Giants to start!