In Japanese mythology an inugami ("dog god") resembling, and usually originating from, a dog, (although other similar species are interpreted as being. e.g., wolves, raccoons, and weasels.) and most commonly carrying out vengeance or acting as guardians on behalf of their "inugami owner." Inugami are extremely powerful and capable of existing independently, (without master or possession) as well as turning on their "owners" and even possessing humans. Even so, while Inugami can betray their masters, they may also be the loyalest of companions.
"Dogs of Japanese legend who possess human bodies. When a person is possessed by an Inugami, he feels pain in his chest, hands, and feet and begins to bark like a dog. People with strong or unstable emotions are thought to be particularly susceptible to being possessed. Inugami are said to originate from the islands of Kyushu and Shikoku. They were sometimes used as objects by Japanese diviners. Since Inugami will not leave a family once they possess it, it was once customary when arranging marriages to check whether the family had an Inugami."
—Shin Megami Tensei IMAGINE Compendium
Inugami can be contracted on Suginami field and are one of the targets of the earlier acts, where players are asked to fuse an Erthys to take advantage of their weakness. They appear regularly within Suginami Tunnels' gold instance and within Shibuya's Quartz instance, where they appear as more powerful variations. The variation in Quartz's gold-level instance will regularly use all four elemental drain area of effect buffs.
Shin Megami Tensei: Strange Journey
"A dog spirit said to possess people in Japanese lore. Those possessed are in a state of "inu-tsuki," and lose conciousness. Onmyoji used them as familiars."
—Shin Megami Tensei: Strange Journey Compendium
Shin Megami Tensei IV Apocalypse
Inugami can be found in the lower areas of Kanda-no-yashiro. It can teach the Fire Breath, Rakunda, Maragi, and Panic Voice skills to Nanashi through its Whisper event. Inugami benefits from learning Fire, ailment, and support skills.
Devil Summoner 2: Raidou Kuzunoha vs. King Abaddon
Inugami appears as an optional boss in Dark Tsukudo-Cho, where he says he is born not of mother and father, but hatred. After his defeat he says he does not want to disappear and so asks Raidou to make him his demon. Depending on the choice he will wish to be reborn as a demon that brings happiness to others if he is allowed to die, while he joins Raidou if he wants to have him. Afterwards Astaroth appears after enjoying the fight.