It was a cold winter day when your best friend, Inosuke, suddenly disappeared. He never came back

Once you were fourteen you learned about all the demons and demon slayer stuff after you were attacked by a demon

Right now, you were walking to your next mission, which you had to do with a group of boys your age. Soon, they arrived, but as you took a closer look at one of the boys, your eyes widened. It was Inosuke