Íluvatar's opponents?

[Eru]

it just means they can't do anything good (if they are wholly evil).

do you mean their intentions aren't good? or they are incapable of doing anything good at all? nothing? i mean, saruman was evil through and through, but when he wrecked the shire, the hobbits made it more beautiful then before. saruman wanted to take revenge, but through his work, it only made things more beauiful. the same can be said of Morgoth. but morgoth was much wiser than saruman, and he wrecked alot more havoc. but, he still made some things more beautilful than before.

iluvatar obviously had a plan from the begining. he dwelt alone until he made the Ainur, who made Music for him. no one else existed until then. and the Ainur were made from Iluvatar thoughts.

i hope that made sense. anyways, what i guess i'm trying to say is that Iluvatar is the ultimate goodness. he has a hand in everything. even if indirectly. example: whenever Manwe had to make an important decison, he delved deep inside him self where iluvatar's thought/will was.