Rather than a ghost, it's more accurate that he's a supernatural being that lives in a separate dimension. The "period of disaster" is most likely a window that connects the two dimensions, causing the "other beings" to be able to enter our dimension.
In conclusion, he's f**king a monster.
i know it's late, but in case you're still wondering, i'm pretty sure the top is based off of Hachishakusama.
Oh most probably. Though he is decidedly less scary looking.
To anyone else, if you want to know more about Hachishakusama (or Hasshakusama), Otherside Picnic (or Isekai Picnic in this site) probably has the most accurate presentation of the urban legend.
And yes, there's an anime.
Also yes, it's a GL manga, though there's no r18 stuff except for the fken scary ghosts.
First time hearing about Hachishakusama. Good info thank youuu
Is seme a ghost or what?