Reading the scroll encloses you in a invisible barrier that extends from you to form a 5-footradius, 10-foot-high cylinder. This barrier prevents fiends from entering or affecting anything within the cylinder. The cylinder remains centered on you as you move. If you move in such a way that a fiend would be inside the cylinder, the effect ends. A fiend can attempt to overcome the barrier by using an action to make a DC 15 Charisma check. On a success, the fiend ceases to be affected by the barrier.