>>41074773
Question: Why does the dragon-fox emit light?
Answer: The dragon-fox is an expedient body of Nyoirin Kannon. It takes the wish-fulfilling gem as its body, and is therefore called King Cintāmaṇi. ... Further, one tradition says that one becomes a king by revering the dragon-fox because the dragon-fox is an expedient body of Amaterasu.
under the name "Fox King," Dakiniten became a manifestation of the sun goddess Amaterasu, with whom the new emperor united during the enthronement ritual. [...] The Buddhist ritual allowed the ruler to symbolically cross over the limits separating the human and animal realms to harness the wild and properly superhuman energy of the "infrahuman" world, so as to gain full control of the human sphere.

The closest to reality they were probably depicted by the Chinese.