Hiroki Kamijou is a fictional character from the light novel series Toaru Majutsu no Index, created by Kazuma Kamachi. He is known for his unique ability called Imagine Breaker, which allows him to negate supernatural powers and abilities. This makes him a central figure in the series, often caught in conflicts between magic and science. Kamijou is depicted as a high school student with a strong sense of justice and a willingness to help others. His character often faces moral dilemmas and challenges, reflecting themes of friendship and sacrifice throughout the series.