An old man chopping wood “misses” his target and splits open the back of his wife’s skull. Oops. The strike is horizontal for some reason. He must like a challenge. She sure must kneel in strange places.
Also, it’s his second wife, who starved the man’s daughter to death after giving all the food to her own kids.
The wound doesn’t heal, but grows into a ravenous demonic mouth. The woman takes on the hunger of the girl she killed.
One night a year, gruesome spirits parade through the streets of Japan. Anyone who crosses their path without protection will perish or get spirited away. Protection consists of precise chants and intonation, so don’t screw it up! You may be better off just staying inside with Netflix and some instant ramen.
Among the rabble you’ll find monsters of all kinds. Minor demons and ghouls, tricksters, reptilian swamp creatures, long-tongued creeps, indistinguishable blob monsters, protruding eyeballs, fang and claw, and a host of animated household objects called Tsukumogami (umbrellas, lanterns, sandals, tea kettles, etc..) who have obtained a spirit by surviving 100 years.