Kongobo Yusei, the true identity of Izutamahiko no Mikoto, was a real shugenja who lived from the end of the Sengoku period to the early Edo period and revived the Mount Zozu/Konpira faith. As the fourth head of the Konkoin, he organized the rites of Konpira Daigongen under the syncretic system of Shinto-Buddhism and Shugendo, and was revered as the restorer of the faith^[1]. Yusei was also a scholar-monk who studied Japanese and Chinese theology from a young age and trained at Mount Koya under the name "Yusei."

In the 11th year of Keicho (1606), Yusei had a statue of himself crafted and enshrined beside the main hall^[2]. Then, on his deathbed in the 18th year of Keicho (1613), he vowed, "I shall die and protect this mountain forever," and legend says he transformed into a tengu and suddenly disappeared. After his death, his spirit was enshrined as the guardian deity "Kongobo," drawing awe as a tengu that protected Mount Zozu. This Kongobo (Konpira-bo) is counted as one of the "Three Great Tengu of Sanuki," alongside Sagamibo and Chujobo of Mount Shiramine^[3].

The sheer cliff towering behind the Okusha/Izutama Shrine, known as "Itoku no Iwa" (Rock of Majestic Virtue), is said to be the historic site where Izutamahiko no Mikoto (Yusei) secluded himself for ascetic practices, and tradition holds that Emperor Sutoku also practiced there. Carvings of a tengu and a karasu-tengu (crow tengu) are engraved on the upper part of the cliff^[4]. Through the separation of Shinto and Buddhism (shinbutsu bunri) in the Meiji era (1868), the guardian deity Kongobo Yusei was redefined as the Shinto deity "Izutamahiko no Mikoto," and the Okusha was renamed "Izutama Shrine," as it remains today. Amulets featuring tengu and karasu-tengu designs are distributed at the shrine, passing down the legend of Yusei transforming into a tengu. Within Kotohira-gu, where the principal deity is Konpira, the god of maritime protection, Izutamahiko no Mikoto embodies the lineage of mountain asceticism and tengu worship, symbolizing the dual nature of the Mount Zozu faith where a sea god and a mountain tengu coexist on the same mountain.