Eä (eh'-uh) and the Halls of Eä are often mentioned in The Silmarillion. Eä and Arda almost seem synonymous, but Eä is the entire universe, Arda and the stars in the sky, but not the Void. Its lord is the one, Eru. Eä, technically is the living universe, The World That Is. It was created at the very beginning, when the Secret Fire became the heart of the Earth.