A demon belonging to Viprachitti’s dynasty. He meditated for a thousand years, chanting the Gayatri mantra to please Brahma, and asked for a boon which would prevent him from being killed in battle. Once he got the boon, he became arrogant, left patala, and challenged Indra. There wa sa divine proclamation that Aruan could not be killed so long as he chanted the gayatri mantra regularly. The devas sent Brihaspati to get Aruna to stop chanting the mantra. When Aruna saw Brihaspati, he asked him why Brihaspati was meeting him, since he was on the opposite side. Brihaspati told him that they were not different, since they both prayed to Gayatri. On hearing that, Aruna decided to abandon the mantra. Gayatri devi was not pleased and sent a swarm of bees towards Aruna and his army. Thus they were killed without a battle, as per Devibhagavata.