Tale of Yokai Hunter

Thousands of years ago, when humanity was still young, the God of Destruction Susanoo no Mikoto opened the Gate of Yomi, causing millions of yokai to flood the human world. Since then, humanities vowed to fight a never-ending battle against the yokai. They called themselves the yokai hunters. The life of Kazahana Sumire, a yokai hunter, has been going rather smoothly, until a new student named Shiba Natsuno comes and turns her world upside down.