In both Hinduism & Buddhism, ‘Deva’ means God, divinity or good spirit. It is believed by some that the word has Indo-European origin from a word meaning celestial bodies. In the Rig Vedas, the Devas are praised to be the creators of the cosmos and a symbol of good. Devotees often term Devas as ‘Devatas’ and female Devas as ‘Devi’. Rig Veda being one of the most ancient religious scriptures, identified thirty-three devas and encompassed multiple writings that could be recited to receive their blessings. These writings are now called slokas or bhajans. As more scriptures were discovered in Hinduism, with more than a hundred million Gods, it became clear that there was an infinite amount of deities in this universe.
With the evolution of the religion over a period of time, there came into being the Hindu Trinity of Gods, Lord Brahma, the creator, Lord Vishnu, the Preserver and Lord Shiva, the destroyer. Many mythological tales and the great epics- Mahabharata & Ramayana, revolve around avatars/forms of these three Gods.
Almost all other devas and their origin roots back to these three superpowers. Devas symbolise eternal good and even with their faults, they never turn to evil means to win a battle.