Tennyo are legendary beings in Japan.
The Japanese Legend
Tennyo is a general term for women who are said to live in heaven and serve as ladies-in-waiting for the gods. In the human world, there is very little difference between tennyo and humans aside from their beautiful appearance. Although they are said to fly in the sky wearing clothing called hagoromo (heavenly kimono), stories passed down about them include one about a tennyo whose hagoromo gets stolen, making her unable to return to the sky, and marries a man living on the earth (the hagoromo legend).
The hagoromo legend is handed down in various places in Japan (from Hokkaido to Okinawa Prefecture) and the Korean Peninsula. Within the study of folklore, there is a theory that the legend is a variation on the story of the Swan Maiden, brought to Japan by visitors from overseas, about a marriage between a human and a non-human being. On the other hand, there is a theory by those who believe in out-of-place-artifacts (OOPArt) and super technology (technology beyond our current capabilities, mainly in science fiction) that goes so far as to regard tennyo as beings from outer space.
Although it is also possible to make a correlation between tennyo and hermits (female hermits) within folklore, the difference between the two is ambiguous.
There is a slight difference in meaning between tennyo and the deification of females (goddesses) in folk beliefs; tennyo themselves are rarely portrayed as having supernatural powers, and because they visit the human world only to give messages and to take care of personal tasks (such as bathing), their existence itself is relatively mundane.
Tennyo are often identified as natural spirits and sprites (fairies) from Western folklore since they have a female form and a similar image.
Relationship to Hiten
Hiten are "people who fly in the sky" who often appear in Buddhist art, and those with a female form are often identified as tennyo. There is one theory that the origin of hiten is in India and another theory claiming that it is in Oriental Persia, but in the latter, it is conjectured that these were people who were originally drawn as a race of winged humans (a form of semi-human or spirit). It is believed that in the process of the idea spreading to the West, they were changed to angels, and in the process of spreading to the East, they changed to hiten and then to tennyo.
Corresponding existences in other cultural regions
Although kinnara spirits in India have the body of a human and the head of a horse in their male form, the female form of kinnari have the image of tennyo. Within Indian mythology as well, tennyo have a form of divine existence and Apsaras are also classified as a kind of tennyo. Apsaras, however, are also identified as nymphs (spirits of water).
In Islam, Houri are regarded in the same light as tennyo. Houri are eternal virgins, and devout muslims are said to receive hospitable treatment from them in heaven (Islam) after death.
Additionally, valkyries in Norse mythology are beings who, under orders of the god Odin, lead men of valor who died in battle to heaven (Valhalla); in a sense, they have a similar image with tennyo in other cultural regions, but from the Norse mythology point of view are not considered to be related.
As a figurative expression
Beautiful women are sometimes figuratively referred to as tennyo. However, this is similar to describing a woman as a goddess, meaning she is worthy of idolization, with the expression itself being a form of personal worship based solely on beauty.