In the narrative lineage of the *Tamura no Soshi*, during the reign of Emperor Kanmu, a demon god named Ootakemaru appeared in the Suzuka Mountains, tormenting travelers crossing the pass and stealing tributes destined for the capital. Tamuramaru, ordered to subdue him, leads a large army to Mount Suzuka, but Ootakemaru flies freely through the air, hides the peaks in black clouds, and causes storms, lightning, and rain of fire to keep the army at bay. Here, the story ceases to be a simple tale of martial valor. Tamuramaru prays to the gods and Buddhas, and through a dream revelation, gains the assistance of Suzuka Gozen. Described as a celestial maiden or Tate-eboshi, the daughter of the Sixth Heaven Demon King, Suzuka Gozen reads Ootakemaru's mind and grants strategies to Tamuramaru. Thus, the subjugation of Ootakemaru is not achieved by a general's power alone; it is accomplished through the combination of a female spirit dwelling on the boundary, divine protection, and the spiritual power of a sacred sword[3][4].

The story of the Suzuka Mountains is significant because it was the boundary of the road leading from the capital to the eastern provinces. The Suzuka Pass divided Ise and Omi, a place where ancient barriers, the Tokaido road, and mountain worship converged. The evil demon in the mountains was not merely a "monster in the deep mountains," but was spoken of as a boundary threat shaking the order of the capital from the outside. Yuji Yamada organizes the Sakanoue no Tamuramaro legend handed down at the Suzuka Pass as a regional tradition linked to the blocking of traffic during the Kusuko Incident, bandits in the Suzuka Mountains, and the origins of Tamura Shrine. Upon this geographical stratum, Ootakemaru is a name born from the overlapping of historical political incidents, temple and shrine origins, Kiyomizu Kannon worship, and Otogizoshi demon-slaying tales[2].

From the Edo period onward, the Tamura story spread to the Tohoku region through Oku-joruri *Tamura Sandaiki*, and Ootakemaru closely merged with demons bearing names like Akuro-o, Ootakemaru (written with different characters), and Takamaru. Variant legends also emerged where the demon slain in Suzuka returns from the underworld, shifting the story's setting to places like Mount Kiri in Mutsu Province, Takkoku-no-Iwaya, and Nonodake Kannon. This movement is deeply tied to the memory of the historical Sakanoue no Tamuramaro as a warrior who conquered the Emishi. Although the Ootakemaru of Suzuka is sometimes identified with Akuro-o of the eastern provinces, there are layers within the Tamura stories that treat them as separate demons; not fixing on a single correct answer is closer to the reality of folklore transmission[5][4].

In modern yokai introductions, Ootakemaru is sometimes spoken of as one of the "Three Great Yokai," alongside Shuten-doji and Tamamo-no-Mae. This classification is not an absolute classical one, but a perspective that aligns giant enemies who challenge the power of the capital, are defeated by the protection of heroes and deities, and whose remains or heads are incorporated into treasures, mounds, and temple origins. Placing Ootakemaru in that corner, while Tamamo-no-Mae bears the political demonic nature of foxes, and Shuten-doji bears the feasting and violence of oni, Ootakemaru rises as the "demon king of the mountains who blocks the pass and ravages the boundary between the capital and the eastern provinces"[1].