The Ainur (singular: Ainu) are the immortal spirits existing before the Creation in J. R. R. Tolkien's fictional universe. These were the first beings made of the thought of Eru Ilúvatar. They were able to sing such beautiful music that the world was created from it.
Some critics have noted the similarity of the Valar to the Æsir, the strong and combative Norse gods of Asgard. Painting by Christoffer Wilhelm Eckersberg, 1817
Other scholars have likened the Valar to Christian angels, intermediaries between the creator and the created world. Painting by Lorenzo Lippi, c. 1645
Cosmology of Tolkien's legendarium
The cosmology of J. R. R. Tolkien's legendarium combines aspects of Christian theology and metaphysics with pre-modern cosmological concepts in the flat Earth paradigm, along with the modern spherical Earth view of the Solar System.
Sketch of one of Tolkien's conceptions of Arda within the Void, Kúma, showing the Encircling Ocean, Ekkaia, and the Starry Heaven, Ilmen, before the creation of Sun and Moon.