In the earliest Ode to Rigveda, Asura was originally the general name of the gods in the sky, but in Avina Veda, it specifically refers to the devil, and the gods are called devas, thus forming the concept of the opposition between gods and demons represented by Asura and devas. The gradual development of this concept of ghosts and gods eventually replaced the original concept of ghosts and gods, which was marked by the war between Indra and Frodo. For example, in Brahma, deva and Asura are depicted as two camps of God and devil. In the later Indian classics, the struggle between the devas and the supreme demon Asura obviously constituted the main theme of myths and legends. Asura's evolution from a primitive god in Indo-China to a demon in Aryan India is probably related to the rise of Indra, the god of emptiness.