It is the style of mask worn by the students of the former Water Hashira Urokodaki! When a demon sees this mask, they know that you'll be trouble. Demon Slayer Fox Mask Embroidered Cuff Beanie for Adults You'll be sure to strike fear into the heartless demons wherever you go wearing this beanie. Aside from the warmth this hat will provide, it is also decorated with a Fox Mask.