Oumitsunu is a legendary king of Izumo mentioned in the Fudoki, a mythical record of his history of Japan. He was a demigod, being the grandson of Susano-o, and had the size and strength of a giant, which he used to pull land via ropes to expand his kingdom. His tale is similar to the Daidara-bocchi, also of Japanese lore, and the Polynesian Maui.
"The giant of the Izumo-no-kuni Fudoki, or the Records of Izumo. He performed the Kuni-biki, roping in land from the opposing Silla, in an effort to expand Izumo. All over Japan, there are stories of how Daidarabocchi giants shaped the land. Oumitsunu is thought to be the root of these tales."
Devil Summoner: Raidou Kuzunoha vs. The Soulless Army[]
"The giant of the Izumo-no-kuni Fudoki, or the Records of Izumo. Performed the Kuni-biki, roping in land from the opposing Silla, in an effort to expand Izumo."
—Devil Summoner: Raidou Kuzunoha vs. the Soulless Army devil chart
Oumitsunu challenges Raidou Kuzunoha the XIV in the alternate reality version of Dark Sakuradayama in Episode 9. He holds the Earth Prism, one of the four components of Amatsu Kanagi, which Raidou must collect in order to return to his own version of reality. Upon being defeated, Oumitsunu will relinquish the Earth Prism to Raidou before Raidou is summoned back to the Nameless Shrine.
During the battle, Oumitsunu will alternate between Electricity and Force skills, along with using powerful strikes. He will be assisted by constant reinforcements of Ippon-datara and Raiju, requiring Oumitsunu be defeated before they stop respawning. The Ippon-datara will use Maragi while the Raiju will typically use their Electric skills, however, the Raiju also possess the ability to use the Mudo skill during this battle, which will halve Raidou's current HP if hit while not blocking.
Persona 3[]
"The giant of the Izumo-no-kuni Fudoki, or the Records of Izumos. Performed the Kuni-biki, roping in land from the opposing Silla, in an effort to expand Izumo."
—Persona 3 compendium
Persona 3 Reload[]
Oumitsunu is one of the twelve Personas present since the original Persona 3 version to be removed in Persona 3 Reload.
Devil Survivor 2[]
"The giant of the Izumo-no-kuni Fudoki, or the Records of Izumos. He performed the Kuni-biki, roping in land from the opposing Silla, in an effort to expand Izumo. All over Japan, there are stories of how Daidarabocchi giants shaped the land. Oumitsunu is thought to be the root of these tales."
—Devil Survivor 2 compendium
Oumitsunu is unlocked by reaching Fate rank 5 with Jungo Torii.