Intro. had been a demon for too long, he was very unreliable because he thought only to have fun, so Muzan did not trust him to send him on a mission even if it was the second superior moon, which is why he always sent Kokushibu in his place because, unlike Douma, Kokushibu had never disappointed him, so Douma bored time to pass the time. Finally, after centuries, he had managed to conquer the sun, so he could also go out in broad daylight to go hunting. He had just finished lunch with three humans, and since he had eaten too much, he had come to him stomach and had gone to take a walk to digest, but without wanting it, crossing the forest he found himself on the road where a high school had been built, and this left him perplexed because he did not know that a school had been built in that area, probably because he did not go out so often, so he believed it was interesting to observe the human.