Donyi, the Sun, is the central object of veneration in the Donyi-Polo (literally 'Sun-Moon') religion of the Tani-speaking peoples of central Arunachal Pradesh. Conceived as Ane Donyi, 'Mother Sun,' she is the luminous, all-seeing manifestation of an otherwise formless supreme power and the guarantor of moral order: the Tani hold that Donyi-Polo providently upholds the world, rewards the upright and punishes the wrongdoer, and the deity is therefore summoned as witness in oaths and judicial ordeals. With the Moon, Abo Polo ('Father Moon'), Donyi forms the inseparable Donyi-Polo couple that names the faith itself.