An Indian god (Sk: deva) or goddess (Sk: devi) of non-Buddhist origin. When referring to such deities, the character "bu 部" is often added to ten, making tenbu 天部. The term ten is used because each of the deities lives in one of the various heavens ten 天 on or above the summit of Mt. Sumeru (Jp: Shumisen 須弥山), the stupendous mountain which rises from the center of the universe in Buddhist cosmology. Ten is one of the six realms rokudō 六道 of transmigration, a form of existence that is pleasant and long, but finite, and does not allow escape from transmigration.
Ten may be divided into groups: those who protect the Buddha and his teachings, and those who are propitiated for good fortune. In the Nara period, there were rather few ten; more were introduced with Esoteric Buddhism mikkyō 密教. They appear in both the Shingon mandara 真言曼荼羅 (*mandara 曼荼羅 of the Shingon sect), some two hundred in the outer court, Gekongōbuin 外金剛部院 or Saigein 最外院, of the *Taizōkai mandara 胎蔵界曼荼羅, and twenty in the *Kongōkai mandara 金剛界曼荼羅. Their appearance in the outer courts suggests their protective function. Many of these ten appear only in these paintings and had no cult. Originally ten were associated with rituals performed for the public good, while later some of them came to be propitiated, first by the aristocracy and then by lower levels of society, for private benefits. Ten are often shown in Japan either as Indian figures or in Chinese dress.