I Tolkiens mytos står ondskan ensam av sin natur.
Från Morgoths Ring , bok 10 av Middle Earths historia , avsnittet "Anmärkningar om motiv i Silmarillion" (betoning min):
Evil is fissiparous. But itself barren. Melkor could not "beget", or have any spouse (though he attempted to ravish Arien, this was to destroy and "distain" her, not to beget fiery offspring). Out of the discords of the Music — sc. not directly out of either of the themes, Eru's or Melkor's, but of their dissonance with regard one to another — evil things appeared in Arda, which did not descend from any direct plan or vision of Melkor: they were not "his children"; and therefore, since all evil hates, hated him too. The progeniture of things was corrupted. Hence Orcs? Part of the Elf-Man idea gone wrong. Though as for Orcs, the Eldar believed Morgoth had actually "bred" them by capturing Men (and Elves) early and increasing to the utmost any corrupt tendencies they possessed.
(Detta är mer eller mindre samma punkt som gjordes i Nerrolkens utmärkta svar , men stöds med en kanon citat från Tolkien själv.)