Glenn Radars

Glenn is lazy, and constantly bored by everything, with his primary focus being sleeping. He becomes the substitute teacher in Sistine's class, after the retirement of her favorite teacher. While he may seem incompetent, he is actually very skilled in magic, but not in the traditional sense. Glenn used to be as passionate about magic as Sistine, but became disillusioned by it due to Sara Silvers' death and his past as the infamous military assassin known as "The Fool." He developed his own type of magic, called "The Fool's World" which negates the activation of all magic within a certain radius, including his own. However, this does not nullify spells that have already been cast. While nullifying the enemies' magic he then beats them using superior hand-to-hand combat skills. He cannot use combat magic coherently due to it being far away from his area of expertise, but he has an in-depth understanding of the concept of all types of magic, which makes him a good instructor.

(Source: Wikipedia)