Hi there. Please forgive me if I am mistaken in anything I say but this is how I remember it. In the chapter "of aule and yavanna" dwarves are made by aule and then allowed to come to life (only when the elves do) but then also yavanna is allowed the Ents, but she doesn't literally create them like aule did his dwarves, right? And then also manwe is then allowed his eagles but again, he doesn't make them does he? I cannot remember the explicit explanation of those two, Ents and eagles. This got me thinking, I know it is told that orcs are corrupted elves and men but what if Eru allowed Melkor to choose a "species" to create. To my understanding Eru is all powerful, and only he knows the true contents of the music, or knows it the most. So, maybe he felt it necessary to allow Melkor, his most gifted valar, to make his own creation to counter balance the three "good" species he allowed the other valar to create. Otherwise there would be an imbalance. Or maybe Eru allowed him to have Glaurung? Balrogs are maia but I don't recall being told precisely how the dragons came about. My apologies is this has come up before, couldn't find it and just wanted to share my thoughts with you all. Thanks!