I'm the Ghost King in Japan

High school student Takizawa Ryosuke seems to spend every day sleeping through class, yet still ranks first in every subject. Secretly, he's the Ghost King, ruler of all manner of spirits and monsters. By day, Takizawa Ryosuke is just a lazy fish who wants to study but can never stay awake; By night, he transforms into a powerful Ghost King, punching man-eating monsters and kicking fallen evil spirits. Competing with priests and shrine maidens for work, and taking care of both demon-slaying and monster-subduing, Takizawa Ryosuke is determined to become a new-generation Ghost King who obeys the law and practices integrity and self-discipline. Here's the serious version (?) of the blurb: As a child, Takizawa Ryosuke awakened the monster blood flowing through him in an accident. He reverted to his ancestral form as Shuten Doji and became the new Ghost King. The Ghost King has appeared, and monsters gather. When countless monsters travel over mountains and rivers, covering thousands of miles to reach the place where the Ghost King was born, ready to pledge their loyalty to their new ruler, they discover that... Their Ghost King is an elementary school student wearing a little yellow hat and carrying a big schoolbag, diligently studying and striving to improve every day. Takizawa Ryosuke, who became the Ghost King at a young age, says: I've taken on a burden no one my age should have to bear! I only wanted to be a top student. Why am I now supposed to be a Ghost King who leads monsters into the modern age and teaches them to obey the law? Takizawa Ryosuke: This is so hard! I really just want to study! P.S. Shuten Doji comes from Japanese monster legends and has nothing to do with the mobile game Onmyoji. All the monsters in this story are either the author's own creations or from Japanese myths and legends. This is not fan fiction based on Onmyoji! Theme: Leading monsters, spirits, and all manner of supernatural beings to obey the law