No substance recurs through Japanese monster-lore like sake. Six distinct relationships, in order of invention:
Sake as weapon. The founding myth sets the pattern: Yamata no Orochi — eight heads, eight vats of eightfold-brewed sake, one massacre. Six centuries of legend later the trick still works at the top of the canon: Shuten-dōji — the demon king whose own name means "drunkard boy" — takes the poisoned cup from disguised guests and dies of hospitality. Japan's greatest monsters are consistently defeated not by force but by conviviality abused — and the shame of that is in the tales: the dying oni's cry that "demons do not lie."
Sake as diplomacy. Offerings run all through the tradition: the yamawaro hauls timber for rice balls and sake, quitting over altered terms; households left cups for the zashiki-warashi's goodwill; the amazake-babaa weaponizes the offer itself at the door — answer and sicken.
Sake as weakness. The kitsune's disguise slips when drunk; the tanuki buys drink with leaf-money; the kawauso was painted by Sekien in a sake-seller's straw hat, bucket in paw — the trickster bench drinks, and it costs them.
Sake as grace. The bestiary's one purely happy drinker: the shōjō, the red sea-sprite who rewards a kind sake-seller with the vat that never empties. Drink as blessing — the Orochi story inverted: here the sea spirit receives the wine honestly, and pays in abundance.
Sake as oracle. At Kibitsu shrine the kettle that once was an oni's voice (narigama) still prophesies over the steam of offerings; and the hyakumonogatari gatherings that generated half this literature were, of course, drinking parties with a lamp-count.
Sake as founding gift. The trade has divine patrons, and the evidence is hanging over every brewery door in Japan. The sugidama — the cedar ball hung out green when the new brew starts and brown by the time it's ready — is Ōmononushi's cedar, from Mount Miwa, whose shrine has no main hall because the mountain itself is the god. Ōyamatsumi, the great mountain god, carries a sake title too.
And the tennyo tale has a variant almost nobody tells: in the Tango type, the heavenly maiden does not simply recover her robe and vanish — she stays with her adoptive parents and blesses them through sake-brewing before departing. A celestial woman as the origin of a brewery — the gentle ending the supernatural-wife genre almost never allows, sitting quietly in the regional record.
The toast: in these stories, how a being handles a cup is its character sheet — monsters die of it, tricksters spend it, spirits are paid in it, and one red gentleman turned it into the only infinite thing in the whole bestiary.