The Zombie System

When a man who has survived throughout the Apocalypse and risen to the peak of all humanity finally dies, what's saying he can't do it again? A story of a young man who lives through an apocalypse and dies to the hand of the world catastrophe type zombie. Who then awakens in his boring math class 2 days before the beginning of the apocalypse. Join this young man as he becomes the strongest in the apocalypse once more!