I became the Lord of the Eternal World in Tokyo.

Uesugi Tetsu travels to Japan and discovers that he can draw cards to transform into demons and ghosts from historical legends.
Furthermore, all the demons and monsters in the world can turn into ashes after death, providing assistance for his next card draw.
【Laughing Prajna】
[Onmyoji's assessment: A minor demon who amuses himself by frightening children; his only strength is his physical body. He is not a cause for concern.]
【…】
【Hundred Eyes Ghost】
[Onmyoji's assessment: Possessing a hundred eyes, though its illusions and dreams can bewitch, its physical strength is insufficient. Its threat is relatively minor.]
【…】
【Gu Huo Niao】
[Onmyoji Evaluation: A nine-headed demon whose fire can incinerate anything and can even take human form to enter the mortal world! Extremely high threat!]
【…】
【Zhu Jiuyin】
[Onmyoji Guild Evaluation: ...]
The world that fell into the abyss a thousand years ago has risen again and is now connected with the human world. This was originally a golden age for demons and ghost stories.
Throughout history, powerful rulers have been eager to make their move—the twelve crowned kings have been ordered to roam the world; Shuten-dōji arrives with a vast empire; Aoandon attempts to once again unleash the Night Parade of a Hundred Demons; and the warlords of the Warring States period raise their banners to mobilize their armies…
Unfortunately, Uesugi Tetsuya, who possessed countless demonic talents, opened his eyes and severed the ties between Yin and Yang.
He shook his head and sighed softly:
"You only know how powerful I am now."
But little did they know—
"How many good brothers have turned into a handful of ashes and fallen on the road I came from."