Does Eru care?

[Inziladun]

Originally Posted by Lotrelf

Melkor being the the offspring of his thoughts, means He also belonged to Eru. Or Eru created him purposefully, perhaps. The purpose of creation of The Dark Lord meant, that to exist good, there should be evil. Otherwise all the words we use to express goodness will have no meaning.

Ah yes. This sticky topic. For what it's worth, I think Ilúvatar's admonition in response to Melkor's alteration of the Music speaks much.

'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.'

The Silmarillion Ainulindalë

Evil was no aberration, but a known quantity to the One, made for his own purpose, dark though it may often be to his creations.