Eru Ilúvatar is the supreme being that created Arda and everything within it ... In this way, there is really only one God of Middle-earth, as all the other created beings (who could be ...
Arda is Tolkien's version of Earth, with Middle-Earth being its main continent where LOTR stories unfold. Arda changed over ...
His mystery posits him as a possible rival to Manwë's claim of the second-most powerful being in all of Arda, but regardless, he didn't create Middle-earth from its foundations like Manwë.