According to legend, Kōga was the son of a local landlord whose wife was kidnapped by tengu. He journeyed to over sixty holy mountains trying to locate her, eventually finding a cave in Mount Tateshina which led to the underworld. On his re-emergence (via Mount Asama) he had become the snake deity Suwa-daimyōjin (more usually identified with the god Takeminakata). There are a number of variants on the basic tale; some see Kōga reunited with his wife (and suggest that they had a son together in the underworld), some involve his two brothers joining him on the search, others include him fighting against a resident serpent god before becoming one himself.
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