Elves who truly hated the black one would never believed his lies again even had he been in the fairest form ever seen in arda.
Here then are my questions:
1.) Why would Eru who loved his children wish them to go trought pain and suffering by reviving the armies lost to morgoth
2.) From where would he get his apocalyptic army?
3.) His body is broken and much of his power is lost where would he get the strenght to break the chains that bind him?
edit: just as a afterthought i would like to thank vir for reminding me that morgoth would return... and i know there can be no specific answers (though i am known to be wrong at times) i would ask you for a theory or thoughts or anything
