A "queda" de Melkor foi que ele queria fazer coisas novas, que queria ir além dos limites de suas próprias habilidades e natureza intrínsecas, que ele queria ser mais do que era (existem paralelos interessantes nisso em outras "quedas" "no Silmarillion e nos trabalhos associados, mas são para outra época):
But as the theme progressed, it came into the heart of Melkor to interweave matters of his own imagining that were not in accord with the theme of Iluvatar, for he sought therein to increase the power and glory of the part assigned to himself. To Melkor among the Ainur had been given the greatest gifts of power and knowledge, and he had a share in all the gifts of his brethren. He had gone often alone into the void places seeking the Imperishable Flame; for desire grew hot within him to bring into Being things of his own, and it seemed to him that Iluvatar took no thought for the Void, and he was impatient of its emptiness.
No entanto:
But being alone he had begun to conceive thoughts of his own unlike those of his brethren.
Então a discórdia de Melkor era de sua própria imaginação, mas Iluvatar o criou com a capacidade de imaginar essa discórdia, ou ele a encontrou por conta própria? Vamos perguntar ao Iluvatar ...
This is your minstrelsy; and each of you shall find contained herein, amid the design that I set before you, all those things which it may seem that he himself devised or added. And thou, Melkor, wilt discover all the secret thoughts of thy mind, and wilt perceive that they are but a part of the whole and tributary to its glory.
(Ênfase minha)
E (caso tenhamos alguma dúvida) ...
And thou, Melkor, shalt see that no theme may be played that hath not its uttermost source in me, nor can any alter the music in my despite. For he that attempteth this shall prove but mine instrument in the devising of things more wonderful, which he himself hath not imagined.
Isso deixa claro. isto parece para os Ainur como se eles tivessem inventado coisas por conta própria, mas no final das contas parece para eles, o que eles fazem é parte da música, conforme dirigido por Iluvatar.
Apenas para reforçar o argumento; existe apenas um ordem de estar em Tolkien, que tem a capacidade de ir além dos limites da música, conforme dirigido por Iluvatar, e isso é Men, e a habilidade foi um presente explícito de Iluvatar:
'...But to the Atani I will give a new gift.'
Therefore to willed that the hearts of Men should seek beyond the world and should find no rest therein; but they should have a virtue to shape their life, amid the powers and chances of the world, beyond the Music of the Ainur, which is as fate to all things else...
Observe em particular a frase "novo presente" aqui; isso é outra coisa que nenhum outro ser teve antes.