Now that you have access to the focusing iris it's time to put that key to use.
As much as I would like to see Malygos brought back into the fold, that's just not going to happen at this point. With everything that's at stake, it is the judgment of the other Dragon Aspects that the Spell-Weaver needs to be put down.
<Krasus says this last with a great deal of trepidation.>
<Name>, travel to the Eye of Eternity, confront Malygos and return with the Heart of Magic.
Only Malygos carries the Heart of Magic. It is his most prized possession.
This is a very sad day, not only for dragonkind, but for all of the living creatures of Azeroth. We have lost one of our most thoughtful, intelligent and ancient friends. Magic is now without its guardian.
Let us hope that this was a wise decision in the coming years, <name>. A storm is still brewing on the horizon and now we are without one of our most powerful defenders.