Demon Soul Illustrated Book

Five-year-old Jin Chenfeng opened a book that must never be opened [The Demonic Soul Illustrated Book]. I thought the family heirloom book on the table leg was a joke, but 13 years later, Jin Chenfeng was told that he would be responsible for opening the book. The demon souls are scattered and hidden throughout the world, and Jin Chenfeng needs to find them one by one and seal them. But what's going on with these demon spirits all over the mountains and plains? There are still people using demon spirits to fight against each other, Pokémon?