Onigajo, or “Demon’s Castle,” is a World Heritage site located on the Kumano coast of Mie Prefecture. Formed over thousands of years by the powerful waves and winds of the Kumano Sea, its cliffs and caves create one of Japan’s most striking natural landscapes. The site takes its name from an ancient legend about a demon defeated by the warrior Sakanoue no Tamuramaro, though no battle actually occurred here. Visitors can walk along a scenic coastal path carved into the rock, passing through sea caves and lookout points that reveal the dynamic beauty of nature’s artistry. Designated as both a National Scenic Site and a Natural Monument, Onigajo captures the essence of Kumano — where the sea, mountains, and faith intertwine.