Daibosatsu' is a Buddhist name, and in the background of the growing syncretism of Shinto and Buddhism, Usa Hachiman was regarded as the deity of guarding the country and protecting Buddhism.
大菩薩は仏教の号で、神仏習合の流れを背景に、宇佐八幡は鎮護国家・仏教守護の神として位置づけられた。