Mishaguji was a native god worshipped in the ancient Shinto region of Japan before the Yamato took control, at which point the worship of it became a taboo. Mishaguji was the god of sexual intercourse and if he was left an offering, then sex would become better. It is said that Mishaguji's incarnation on Earth had a very phallic shape, possibly similar to an earthworm, and he would take shelter under rocks or stones. Once Yamato took control however, Mishaguji became seen as a god that only the undesirable and unfaithful would worship.
"A native god worshiped in the Shinano region before the Yamato power took control. Said to be a god born from the ancient belief that rocks and stones housed divine spirits."
—Devil Summoner: Soul Hackers 3DS Compendium
Devil Summoner: Raidou Kuzunoha vs. The Soulless Army