A Big Boss in the World of Immortality Secretly Suppresses Demons in College

When the Demon Lord is about to tear the two worlds apart, the savior is nowhere to be found in the world of immortality, and he is staying up late studying for his final thesis. She is the descendant of the sword and sound master who hides in the city. She attends classes and works part-time during the day, and slays demons at night. On campus, the librarian is a retired elder, the physics genius is both an opponent and an ally, and even the roommates have ancient bloodlines. In this seemingly ordinary university, the guardians use their mortal bodies to weave barriers, modify memories, and maintain the calm appearance of modern society. When the countdown to doomsday comes, they must set up the last line of defense between the classroom, library and rooftop - using youth as their front and ordinaryness as their disguise, they must fight an unknown cross-border battle for protection.