The three main kinds of gods are celestial, atmospheric, and terrestrial. Their attributes shift, and one god can be identified with another or take on his or her powers. The most important gods are Agni, the fire god, who plays a central role in the sacrifice, and Indra, the warrior god and thunder god, celebrated for his slaying of the drought demon Vritra. Several solar deities are found, including Surya, Savitri, Pushan, and Vishnu . Varuna is the all-seeing god of justice, guardian of the cosmic order or rita.
Soma personifies the plant whose intoxicating juice was offered as an oblation.
With the passage of time the sacrifice became increasingly elaborate, and priests became highly skilled specialists. The conception of the sacrifice's meaning also developed. Correlations were made between parts of the sacrifice and of the cosmos. The sacrifice came to be regarded as the fundamental agency of creation, embodied in brahman, the mystical power of speech in the mantras. Theories of cosmogony and the idea of a single underlying reality found clear expression in philosophical hymns and the later interpretive works.