The Demon of Zero was a Japanese light novel written by Yu Kano and first published in 2002. The story mainly tells the story of a demonic spirit named Louise Greillat who embarked on an adventure in the foreign world, the Kingdom of Ailun. In the otherworld, magic and technology coexisted. The envoys used the power of magic and technology to explore new knowledge and improve their abilities. Louise and her companions encountered various dangers and challenges in their adventures, and at the same time, they made many like-minded friends. Together, they overcame many difficulties and eventually became powerful and useful messengers. This novel was very popular not only in Japan but also in China.