Nikko Bosatsu and Gakko Bosatsu are described as the main Buddha in the Buddhist paradise of Yakushi-Nyorai, the realm known as Joruri or Pure Lapis Lazuli in the eastern quarter, Vaiduryanirbhasa in Sanskrit in "Yakushi Hongan-kyo Sutra," and it can be said that there is neither faith nor statues of Nikko Bosatsu and Gakko Bosatsu individually, other than the statues of the Kyoji of Yakushi-Nyorai.
日光菩薩・月光菩薩は『薬師本願経』に、薬師如来の浄土である東方瑠璃光世界の主要な菩薩であるとして言及されるが、薬師如来の脇侍として造像される以外に、日光菩薩・月光菩薩単独での信仰や造像はないと言ってよい。